Схема Электрическая Принципиальная Щита Распределительного

В них находятся коммутационные защитные устройства, которые выполняют все перечисленные выше функции. Устройство для контроля расхода электроэнеогии.

Приложить к стене корпус. Важно пользоваться конкретными рекомендациями и соблюдать определенные правила.

Монтаж электрического щитка представляет собой сложную процедуру, которая выполняется в строгой последовательности.
⚡⛔ СБОРКА распределительного щитка в квартире. Как собрать бюджетный электрический щит своими руками

Однако все сложные понятия и процессы могут быть представлены в виде простых рекомендаций.

У него есть несколько функций: Он должен принимать энергию от внешнего источника. Далее идут однополюсные групповые автоматические выключатели.

Нулевые рабочие проводники остальных групп, которые защищены обычными автоматическими выключателями, подключаются на вводную общую нулевую шину. В соответствии с этим проектом производится покупка и последующий монтаж распределительного электрощита.

Принципиальные электрические схемы щитов распределительных и освещения с комментариями Схема 1 Принципиальная электрическая схема осветительного щита на 12 автоматов защиты, ОЩВ

Количество модулей в распределительных щитах различаются в зависимости от фирмы производителя.

Электрощит в квартире. Распределительный щит

Электрический щиток в квартире

Нулевые рабочие проводники остальных групп, которые защищены обычными автоматическими выключателями, подключаются на вводную общую нулевую шину. Популярной системой защиты от протечек воды является Neptun.

Если его установку решено проводить самостоятельно, следует знать несколько обязательных правил распределения: Потребители, которые берут на себя больше всего энергии, должны выделяться в специальные группы. Если электрические розетки устанавливаются во влажных помещениях, следует использовать УЗО, рассчитанное на дифференциальный ток 10 мА.

Нижние и боковые края совместить с разметкой. Главная Электрика Схемы электропроводки квартиры Принципиальные электрические схемы распределительных электрощитов 22 схемы Принципиальные электрические схемы распределительных электрощитов 22 схемы Схемы электропроводки квартиры Распределительные электрощиты предназначены для разделение электропроводки на групповые цепи.

Так поступают со всеми жилами. Водонагреватель, стиральная машина, кондиционер также можно запитать через амперные автоматы.

Щит на пять групп. Вариант 3 Как я выше писал, что все группы розеток должны иметь защиту от утечек тока, то есть должны защищаться с помощью УЗО.

Схема электрического щита должна отвечать требованиям ГОСТа.

Так как практически все соединения между защитными устройствами описаны в первом варианте, то особо комментировать тут нечего. При создании качественной проводки следует понимать, как осуществляется физика процесса.
УЗО или ДИФ автомат, что выбрать? Секреты качественного электромонтажа

Что это такое

Подготовка проводов Сначала необходимо приблизительно подогнать их по длине.

Это необходимо учитывать, зная, что в это же время вокруг будут ходить маляры и шпаклевщики.

Пунктиром 1 обозначен корпус распределительного щита, 2 и 3 это нулевая и заземляющая шина. Для исключения одновременного срабатывания вводного и группового устройств на вводе рекомендуется ставить селективное УЗО.

Это может быть автоматический выключатель или рубильник выключатель нагрузки. Фото — ГРЩ Групповой электрощит используется для контроля отдельных групп потребителей тока светильников, бытовых приборов и т.

Чтобы защитить электрическую систему от перенапряжения, используются рубильники, размыкающие электрическую сеть под нагрузкой. У каждого специалиста своё мнение на этот счет.

Буквенные обозначения в схемах

При помощи болгарки выполняются резы по периметру ниши. Выполняют качественную сборку электрических щитов профессиональные электрики, однако при соблюдении определенных правил такая работа может быть выполнена самостоятельно. Для этих целей ставятся устройства защитного отключения УЗО или дифавтоматы с током утечки мА. При согласовании придется выполнять усиление согласно новому проекту и проведение различных работ. Именно поэтому лучше, чтобы щиток был оборудован съемной рамкой с рейками.

Уличные модели обычно оснащаются стеклянным окошком, которое позволяет считывать данные счетчика. В щите запланированы три автомата защиты, на три группы. Лучше, если щиток будет установлен в тамбуре. Провода может просто залить из квартиры сверху.

Далее идут однополюсные групповые автоматические выключатели. Xn — клеммы подключений. Водонагреватель, стиральная машина, кондиционер также можно запитать через амперные автоматы.
Т 12.2 Схемы сборки группового квартирного щитка

Принципиальные электрические схемы щитов распределительных и освещения с комментариями

Это электромеханическое устройство, объединяющее в себе автомат защиты от короткого замыкания и УЗО устройство защитного отключения для защиты человека от токов утечки. Ну и бывают еще просторные квартиры с электрическим отоплением и группой мощных потребителей электроэнергии.

Всех сложностей можно избежать, если сразу приобрести более дорогую конструкцию, отвечающую всем требованиям ГОСТа. Однако такое решение не очень современно и не самое эффективное.

Содержание: Частный дом Квартира Итак, если квартира старой постройки и, к тому же, однокомнатная к примеру, хрущевка , тогда проект расключения электропроводки будет выглядеть следующим образом: Однолинейный проект Как Вы видите, в данной схеме подключения распред щитка нет PE шины, так как в старых хрущевках заземление отсутствует.

Шины подсоединения проводов. Современные щитки способны следить за качеством энергии, которая поступает потребителю, и при необходимости реагирует на это. Линия может быть оборудована трехжильным электрическим кабелем, имеющим сечение 2,5 кв. Нижние и боковые края совместить с разметкой.

Виды щитов

Чтобы защитить электрическую систему от перенапряжения, используются рубильники, размыкающие электрическую сеть под нагрузкой. Для его размещения на стене, необходимо учесть высоту от пола до его нижнего края не менее — 1,4 м, а расстояние верхнего края от пола не более 1,8 м. Сколько в ней проводов, показано при помощи наклонных черточек. В третьем варианте схемы представлено вводное УЗО, которое устанавливается после счетчика.

Для этого понадобится удлинитель. У каждого специалиста своё мнение на этот счет. При правильной организации ввода кабелей установка модульного оборудования будет существенно облегчена. Рядом со щитком не следует размещать легко воспламеняющихся предметов и веществ.

Выбор комплектующих и аксессуаров для электрического щита

Он предотвращает короткие замыкания. Это схема электропитания помещения по ,так называемой, схеме заземления TN-C-S. Она должна располагаться вблизи автомата ввода.

Фото — большой ГРЩ Технические требования к устройству обозначены в ГОСТе общие характеристики распределительных щитов : Устройство обязательно должно иметь высокий класс защиты от воспламенения. Или каких нибудь пристроек к дому. Плохой параметр бесперебойности питания дома! Место в электрощите для установки одного устройства защиты называется модулем. Кроме того, следует установить реле напряжения, которое будет следить за его показаниями в сети.
Компоновка и сборка 3-фазного распр. щита для дома от КЭАЗ

Проектирование освещения офисов (часть 2)

     Автоматические выключатели для групповых линий взяты с номинальным током 10 А и характеристикой срабатывания «С». Что бы предотвратить ложные срабатывания автоматических выключателей они должны выбираться с учетом возможного нагрева выключателей как от проходящего по ним тока, так и вследствие повышенных температур окружающей среды. Номинальные токи автоматических выключателей приводят при температуре окружающей среды 25 градусов. При этом номинальный ток уменьшается примерно на 5-6% при повышении температуры окружающей среды на каждые 10 градусов. Для групповых линий желательно иметь рабочий ток, не превышающий 0,7-0,75 от номинального тока автоматического выключателя. Для некоторых типов светильников необходимо учитывать пусковые токи, возникающие в момент зажигания ламп.

    Номинальный ток вводного автоматического выключателя следует выбирать наименьшим по расчетным токам, но таким образом, что бы аппарат защиты не отключался при кратковременных перегрузках (от пусковых токов). Данное требование отражено в п. 3.1.4 ПУЭ.

    При этом номинальный ток теплового расцепителя должен, как минимум, на 10% превышать расчетный ток электроустановки.

    Вводной автоматический выключатель возьмем с номинальным током 20 А, выключатель в ВРУ при этом должен иметь номинальный ток не менее 32 А, что бы обеспечить условие селективности. То есть при перегрузке или коротком замыкании должен отключаться вводной автомат в нашем щите, а не в ВРУ. При выборе номинала вводного автоматического выключателя необходимо учитывать возможное неравенство токов в наименее и наиболее нагруженных фазах. В соответствии с п.9.5 в СП 31-110-2003 допускается неравенство токов до 30% в пределах одного щитка и не более 15% в начале питающих линий.

    Кабель, питающий щит освещения, по условиям длительно допустимого тока выбирается по номиналу аппарата защиты, установленного в ВРУ (то есть по току 32А). По данному показателю достаточно иметь сечения жил кабеля 6 мм². Но для уменьшения потерь и сопротивления цепи фаза-ноль его сечение увеличено до 10 мм².

        Для определения токов короткого замыкания необходимо вычислить сопротивление цепи фаза-ноль наиболее протяженных линий, или определить максимально допустимую длину кабеля групповой линии при заданном сечении жил. Для автоматических выключателей групповых линий с номинальным током 10 А и характеристикой срабатывания «С» ток короткого замыкания должен превышать значение 10А*10*1,2=120А. При номинальном напряжении 220В допустимое сопротивление цепи фаза – ноль должно быть менее величины R_max=220В/120А=1,83 Ом. Вычислим максимальную длину кабелей групповых линий с сечениями жил 1,5 мм² и 2,5 мм², при которых будут соблюдаться условия согласования параметров цепи с характеристиками аппаратов защиты. Исходные данные для этого расчета:

-трансформатор ТП 1000 кВА, соединен по схеме треугольник – звезда.

-кабель питающей сети (от шин 0,4 кВ ТП до ВРУ) 4*150 мм² с медными жилами длинной 190 метров;

-кабель распределительной сети (от ВРУ до щита освещения) 5*10 мм² с медными жилами длиной 40 метров;

Используя приведенные в статье «Сопротивление цепи фаза-ноль» таблицы и методы расчета получаем сопротивление источника питания от шин ТП до клемм автоматических выключателей групповых линий R_и.п.=0,26 Ом. Тогда допустимое сопротивление кабеля групповой линии составит величину R_гр.max=R_max— R_и.п.-R_дуги=1,83-0,26-0,12=1,45 Ом. Здесь R_дуги=0,12 Ом — активное сопротивление дуги.

Искомая максимальная длина групповой линии с сечением жил 1,5 мм² равна:

L_1,5=1,45 Ом /(29,1 Ом/км)=0,050 км (или 50 метров), здесь 29,1 Ом/км – удельное сопротивление кабеля (фазной и нулевой жил) сечением 1,5 мм² при температуре 65 градусов.

При сечении жил 2,5 мм² максимальная длина групповой линии составит:

L_2,5=1,45 Ом /(17,46 Ом/км)=0,083 км (83 метра), здесь 17,46 Ом/км – удельное сопротивление кабеля (фазной и нулевой жил) сечением 2,5 мм² при температуре 65 градусов.

    Исходя из проведенных вычислений кабель для групповой линии 5 необходимо взять с сечением 2,5 мм², остальных групп – 1,5 мм².

    Расчет потерь необходимо выполнить для всех групповых линий. При этом следует учитывать, что на участке линии от щита освещения до выключателя по кабелю проходит ток всех светильников группы. При использовании двухклавишного выключателя ток разветвляется на два направления. Потери в кабеле после выключателя следует определять для одного (более протяженного и нагруженного участка линии). Кроме того, для уменьшения потерь и сопротивления цепи фаза–ноль, целесообразно от каждой клавиши проводить отдельный кабель к каждому ряду светильников, как показано на Рис. 4. На данном рисунке показана монтажная схема помещений 1 и 4. Такую схему часто делают для всех помещений, что бы упростить работу монтажникам и уменьшить вероятность ошибок при монтаже.

 

Рис. 4 Монтажная схема помещений 1 и 4

    При расчете потерь Гр-О-1 выделены три участка: от щита до выключателя помещения 4; от выключателя помещения 4 до выключателя помещения 1, от выключателя помещения 4 до наиболее удаленного светильника. На первом участке потери в линии создают все светильники группы, на втором светильники помещения 1 и на третьем светильники, отходящие от клавиши №1 (выделены красным цветом). Потери вычисляются на каждом участке, и затем складываются.

    Потери, как указано в статье «Нормирование потерь в осветительных сетях», должны быть не более 2,5% на участке сети от ВРУ до наиболее удаленного светильника при величине потерь менее 4,5% на участке сети от шин 0,4 кВ ТП до ВРУ. В нашем случае потери питающей линии не превышают 3% (кабель с медными жилами сечением 150 мм², длиной 190 метров при мощности 150 кВт).

    Потери распределительной сети (от ВРУ до ЩО) не превышают 0,45% (кабель с медными жилами сече6нием 10 мм², длиной 40 метров при мощности 7,83 кВт). Следовательно, в групповых линиях рассматриваемой осветительной установки мы можем допустить потери 2,05%.

    В ГОСТы и другие руководящие документы, в которых содержатся требования к проектированию освещения, часто вводятся изменения и дополнения. Поэтому всегда необходимо следить за всеми изменениями в существующих документах и быть в курсе введения в действие новых стандартов.

                                                                                                                                        Виктор Чернов

                                                                                                                                        8 сентября 2013 г.

    К первой части статьи

    К ОГЛАВЛЕНИЮ (Все статьи сайта)

    К разделу  СВЕТИЛЬНИКИ 

90000 Learn To Interpret Single Line Diagram (SLD) 90001 90002 Single line diagram (SLD) 90003 90004 We usually depict the electrical distribution system by a graphic representation called a 90005 single line diagram (SLD) 90006. A single line can show all or part of a system. It is very versatile and comprehensive because it can depict very simple DC circuits, or a very complicated three-phase system. 90007 90008 Learn To Interpret Single Line Diagram — SLD (on photo: An example of 66/6.6kV power substation single line diagram) 90004 We use 90005 universally accepted electrical symbols 90006 to represent the different electrical components and their relationship within a circuit or system. To interpret SLDs you first need to be familiar with the electrical symbols. This chart shows the most frequently used symbols. 90007 90013 90014 90015 90016 Individual electrical symbols 90017 90018 90015 90020 Symbol 90017 90020 Identification 90017 90020 Explanation 90017 90018 90015 90020 90029 90029 90017 90020 Transformer 90017 90020 Represents a variety of transformers from liquid filled to dry types.Additional information is normally printed next to symbol indicating winding connections, primary / secondary voltages and KVA or MVA ratings. 90017 90018 90015 90020 90039 90039 90017 90020 Removable or drawout circuit breaker 90017 90020 Normally represents a MV drawout circuit breaker 5kV and above. 90017 90018 90015 90020 90049 90049 90017 90020 Future removable or drawout circuit breaker position 90017 90020 Represents a structure equipped to accept circuit breaker in the future, commonly known as provisions.90017 90018 90015 90020 90059 90059 90017 90020 Non-drawout circuit breaker 90017 90020 Represents a fixed mounted low voltage circuit breaker. 90017 90018 90015 90020 90069 90069 90017 90020 Removable or drawout circuit breaker 90017 90020 Represents a drawout low voltage circuit breaker. 90017 90018 90015 90020 90079 90079 90017 90020 Disconnect switch 90017 90020 Represents a switch in low or medium / high voltage applications (open position shown) 90017 90018 90015 90020 90089 90089 90017 90020 Fuse 90017 90020 Represents low voltage and power fuses.90017 90018 90015 90020 90099 90099 90017 90020 Bus duct 90017 90020 Represents low and medium / high voltage bus duct. 90017 90018 90015 90020 90109 90109 90017 90020 Current transformer 90017 90020 Represents current transformers mounted in assembled equipment. A ratio of 4000A to 5A shown. 90017 90018 90015 90020 90119 90119 90017 90020 Potential or voltage transformer 90017 90020 Represents potential transformers usually mounted in assembled equipment. A ratio of 480V to 120V shown.90017 90018 90015 90020 90129 90129 90017 90020 Ground (earth) 90017 90020 Represents a grounding (earthing) point 90017 90018 90015 90020 90139 90139 90017 90020 Battery 90017 90020 Represents a battery in an equipment package 90017 90018 90015 90020 90149 90149 90017 90020 Motor 90017 90020 Represents a motor and is also shown with an «M» inside the circle. Additional motor information is commonly printed next to symbol, such as horsepower, RPM and voltage.90017 90018 90015 90020 90159 90159 90017 90020 Normally open (NO) contact 90017 90020 Can represent a single contact or single pole switch in the open position for motor control 90017 90018 90015 90020 90169 90169 90017 90020 Normally closed (NC) contact 90017 90020 Can represent a single contact or single pole switch in the closed position for motor control 90017 90018 90015 90020 90179 90179 90017 90020 Indicating light 90017 90020 The letter inside circle indicates the color.The color red is indicated. 90017 90018 90015 90020 90189 90189 90017 90020 Overload relay 90017 90020 Protects a motor should an overload condition develop. 90017 90018 90015 90020 90199 90199 90017 90020 Capacitor 90017 90020 Represents a variety of capacitors. 90017 90018 90015 90020 90209 90209 90017 90020 Ammeter 90017 90020 A letter is usually shown to designate the meter type (A = ammeter, V = voltmeter, etc.) 90017 90018 90015 90020 90219 90219 90017 90020 Instantaneous overcurrent protective relay 90017 90020 The device number designates the relay type (50 = instantaneous overcurrent, 59 = overvoltage, 86 = lockout, etc.) 90017 90018 90015 90020 90229 90229 90017 90020 Emergency generator 90017 90020 The symbol is frequently shown in conjuction with a transfer switch. 90017 90018 90015 90020 90239 90239 90017 90020 Fused disconnect switch 90017 90020 The symbol is a combination of a fuse and disconnect switch with the switch in the open position. 90017 90018 90015 90020 90249 90249 90017 90020 Low voltage motor control 90017 90020 The symbol is a combination of a normally open contact (switch), overload relay, motor and disconnect device.90017 90018 90015 90020 90259 90259 90017 90020 Medium voltage motor starter 90017 90020 The symbol is a combination of a drawout fuse, normally open contact (switch) and motor. 90017 90018 90015 90020 90269 90269 90017 90020 Meter center 90017 90020 A series of circle symbols representing meters usually mounted in a common enclosure. 90017 90018 90015 90020 90279 90279 90017 90020 Load center or panelboard 90017 90020 One circuit breaker representing a main device and other circuit breakers representing feeder circuits usually in a common enclosure.90017 90018 90015 90020 90289 90289 90017 90020 Transfer switch 90017 90020 • Circuit breaker type transfer switch 90295 • Non-circuit breaker type transfer switch 90017 90018 90015 90020 90300 90300 90017 90020 Current transformer with connected ammeter 90017 90020 The instrument connected could be a different instrument or several different instruments identified by the letter. 90017 90018 90015 90020 90310 90310 90017 90020 Protective relays connected to current transformer 90017 90020 Device numbers indicate types of relays connected, such as: 90295 • 67 — Directional overcurrent 90295 • 51 — Time overcurrent 90017 90018 90320 90321 90322 Simple electrical circuit 90323 90004 Now, that you are familiar with electrical symbol, let’s look at how they are used in interpreting single line diagrams.Below is a 90005 simple electrical circuit 90006. 90007 90328 90328 Figure 1 — Simple single line diagram 90004 You can tell by the symbols that this single line diagram has three resistors and a battery. The electricity flows from the negative side of the battery through the resistors to the positive side of the battery. 90007 90295 90322 Industrial single line diagram 90323 90004 Now, lets go through a industrial single line diagram. When interpreting a single line diagram, you should always start at the top 90005 where the highest voltage is 90006 and work your way down to the lowest voltage.This helps to keep the voltages and their paths straight. 90007 90004 90005 To explain this easier, we have divided the single line into three sections. 90006 90007 90343 90343 Figure 2 — A typical industrial single line diagram 90345 Area A // 90346 90004 Starting at the top, you will notice that a transformer is feeding power to the whole system. The transformer steps the voltage down from 35kV to 15kV, as indicated by the numbers next to the transformer symbol. Once the voltage has been stepped down, a drawout circuit breaker (90005 a1 90006) is encountered.90007 90351 90004 Do you recognize 90005 the drawout circuit breaker 90006 symbol? 90007 90356 90004 You can assume this circuit breaker can handle 90005 15kV 90006, since it is attached to the 15kV side of the transformer, and nothing different is indicated on the single line diagram. Following the drawout circuit breaker (90005 a1 90006) from the transformer, it is attached to a heavier, horizontal line. 90007 90004 This horizontal line represents an 90005 electrical bus 90006, which is a means used to get electricity to other areas or circuits.90007 90295 90345 Area B // 90346 90004 You will notice that 90005 two more drawout circuit breakers (b1 and b2) 90006 are attached to the bus and feed other circuits, which are at 15kV, since there has been no indication of voltage change in the system. Attached to the drawout circuit breaker (90005 b1 90006), a step-down transformer is used to take the voltage in that area of ​​the system from 15kV down to 5kV. 90007 90376 90376 SLD area B 90004 On the 5kV side of this transformer, a 90005 disconnect switch 90006 is shown.The disconnect is used to connect or isolate the equipment below it from the transformer. The equipment below the disconnect is at 90005 5kV 90006, since nothing indicates the contrary. 90007 90351 90004 Do you recognize the equipment attached to the lower side of the disconnect switch as being 90005 two medium-voltage motor starters 90006? 90007 90356 90004 A number of starters could be connected depending upon the particular system requirements. Now locate the second drawout circuit breaker (90005 b2 90006).This circuit breaker is attached to a fused disconnect switch and it is connected to a step-down transformer. Notice that all the equipment below the transformer is now considered low voltage equipment, because the voltage has been stepped down to a level of 90005 600 volts or lower 90006. 90007 The last piece of electrical equipment in the middle portion of the diagram is another circuit breaker (90005 b3 90006). This time, however, the circuit breaker is a 90005 fixed low voltage circuit breaker 90006, as indicated by the symbol.90004 Moving to the bottom area of ​​the single line diagram, notice that the circuit breaker (b3) in the middle is connected to the bus in the bottom portion. 90007 90295 90345 Area C // 90346 90004 To the bottom left and connected to the bus is another fixed circuit breaker. Look carefully at the next grouping of symbols. 90007 90351 90004 Do you recognize the automatic transfer switch symbol? 90007 90356 90004 Also, notice that a circle symbol which represents an 90005 emergency generator 90006 is attached to the automatic transfer switch.This area of ​​the single line diagram tells us that it is important for the equipment connected below the automatic transfer switch to keep running, even if power from the bus is lost. You can tell from the single line diagram that the automatic transfer switch would connect the emergency generator into the circuit to keep equipment running, if power from the bus were lost. 90007 90415 90415 SLD area C 90004 A low-voltage motor control circuit is attached to the automatic transfer switch through a low-voltage bus.90005 Make sure you recognize these symbols. 90006 Although we do not know the exact function of the low voltage motor control in this circuit, it is obvious that it is important to keep the equipment up and running. A written specification would normally provide the details of the application. 90007 90004 On the right side of the third area there is another fixed circuit breaker connected to the bus. It is attached to a 90005 meter center 90006, as indicated by the 90005 symbol formed by three circles 90006.This indicates that the electric company is using these meters to keep track of power consumed by the equipment below the meter center. 90007 90004 Below the meter center is a load center or panelboard that is feeding a number of smaller circuits. This could represent a load center in a building that feeds power to the lights, air conditioning, heat and any other electrical equipment connected to the building. 90007 90322 Few more words // 90323 90004 This over-simplified analysis of a single line diagram gives you an idea of ​​the kind of story such diagrams tell about 90005 electrical system connections and equipment 90006.90007 90004 Just keep in mind that although some single line diagrams may appear overwhelming by virtue of their size and the wide variety of equipment represented, they can all be analyzed using the same step-by-step method. 90007 90004 90438 90005 Reference // 90006 Fundamentals of Electrical Distribution by EATON 90441 90007 .90000 Electrical Transformer Symbols — Single Line Transformer Symbols 90001 90002 Transformer Symbols — Single Line Transformer Symbols 90003 90004 Following is a list of different types of transformer symbols. The single line transformer symbols list is given below at the end of the post. 90005 90004 90007 90007 90005 90004 90011 Two Winding Transformer 90012 90005 90004 90015 90015 90005 90004 This is a generic symbol of a two winding transformer is single line representation. Two winding transformers are made up of two winding connected together through the varying magnetic flux.90005 90004 90011 Single Phase two Winding Transformer 90012 90005 90004 90025 90025 90005 90004 This is SLD (single line diagram) representation of single phase two winding transformer. Such transformer has two winding i.e. primary and secondary both used by the single phase. It has two primary terminals and two secondary terminals. 90005 90004 90011 Air Core Transformer 90012 90005 90004 90035 90035 90005 90004 These symbols represent air core transformer. An air core transformer has no magnetic core, instead the winding is wound around a plastic (nonmagnetic material) or there is no core at all.There are core losses in magnetic core that increases with frequency which is why air core transformer is used for radio frequency applications. 90005 90004 90011 Saturable Reactor Transformer 90012 90005 90004 90045 90045 90005 90004 This is a type of transformer whose core can be saturated on purpose. Core saturation is the point where the core is fully magnetized and producing maximum flux. The core saturation is controlled using DC control winding. During saturation, the reactance decreases that result in increasing of the current flow.90005 90004 90011 Iron Core Transformer 90012 90005 90004 90055 90055 90005 90004 The core of this transformer is made up of iron. The iron has high magnetic permeability which allows it to carry high magnetic flux thus increasing the induction between the windings. The disadvantage of iron core is eddy current loss (core loss) which depends on supply frequency. Thus they are used for low frequency applications. 90005 90004 90011 Ferrite Core Transformer 90012 90005 90004 90065 90065 90005 90004 This symbol represents a transformer made up of ferrite core.The ferrite is a magnetic material having very high magnetic permeability which increases the flux inside the core of the transformer. Also ferrite has very low electrical conductivity which decreases the eddy current losses occurring inside the core. 90005 90004 90011 Variable Transformer 90012 90005 90004 90075 90075 90005 90004 A variable transformer is a type of transformer that can provide a variable secondary voltage from the same primary voltage. It can vary the output voltage by changing the number of turns or using different tap points or by variable coupling.A Variac is the most common variable autotransformer. 90005 90004 90011 Single Phase Separate Winding Transformer 90012 90005 90004 90085 90085 90005 90004 This is an SLD representation of a single phase transformer with separate winding for primary & secondary terminals. The double dashed line represents two terminals for each winding. 90005 90004 90011 Shielded Transformer 90012 90005 90004 90095 90095 90005 90004 Shielded transformer has an electrostatic shield between the primary & secondary winding that prevents the transfer of huge spikes of voltage & high frequency noise.The shield is grounded & The capacitance between the shield and the primary winding prevents the noise transfer due to high frequency. 90005 90004 90011 Current Regulation Transformer 90012 90005 90004 90105 90105 90005 90004 Such type of transformer provides constant current even if the voltage increases or decreases. Storable core transformer regulates the current by saturation the core using DC control winding. 90005 90004 90011 Voltage Regulation Transformer 90012 90005 90004 90115 90115 90005 90004 Voltage regulation of a transformer means maintaining the secondary voltage constant over a range of load.This kind of transformer regulate its voltage i.e. provide constant voltage with increasing or decreasing the load current. 90005 90004 90011 Moving magnet Transformer 90012 90005 90004 90125 90125 90005 90004 As the name suggest, the voltage in this transformer coil is induced by the movement of the magnet in close proximity to the coil. Phono cartridge uses MM transformer & it converts the movement of the stylus into electrical signal by moving the magnet attached to its tips. 90005 90004 90011 Adjustable Core Transformer 90012 90005 90004 90135 90135 90005 90004 Such type of transformer has an adjustable core which increases or decreases the flux linkage between the windings to increase or decrease the current flow.Such type of transformers is used for current control in welding applications. 90005 90004 90011 Current Transformer 90012 90005 90004 90145 90145 90005 90004 Current transformer is a type of instrument transformer used for decreasing high alternating current in a line down to safe levels for measurement purposes. The current produced in its secondary is proportional to the current in its primary (conductor) & it is measured by connecting it with a conventional Ammeter. 90005 90004 90011 Dual Core Current Transformer 90012 90005 90004 90155 90155 90005 90004 Such type of current transformer has two cores.There is a single conductor (primary) going though both of the cores of the transformer. The double core of the transformer increases the rating of the transformer. 90005 90004 90011 Dual Core Current Transformer with Two Secondary Lines 90012 90005 90004 90165 90165 90005 90004 This is a dual core current transformer that has two cores each with individual secondary winding. Each winding offers different turn ratio providing access to two different current ratings on each individual windings.90005 90004 90011 Current Transformer with 3 Conductors 90012 90005 90004 90175 90175 90005 90004 Such type of CT is also known as CBCT (Core Balance Current Transformer). It has 3 primary conductors (3 phases) running through its core. The total vector sum of the current in normal condition is zero. When there is an earth fault current, the difference appears through the CBCT which is connected to the alarm system. 90005 90004 90011 Single Core CT with two Secondary & 3 Primary Conductors 90012 90005 90004 90185 90185 90005 90004 This symbol represents a current transformer having 2 secondary windings on a single core.There are 3 primary conductors running through its core. The individual secondary winding provides different current rating & turns ratio. 90005 90004 90011 Single Core Current Transformer with two Secondary 90012 90005 90004 90195 90195 90005 90004 Such type of Current transformer has two secondary winding on a single core. Each winding provide different turn ratio offering different current ratings. 90005 90004 90011 Choke 90012 90005 90004 90205 90205 90005 90004 Choke is a made up of two separate windings wounded on the same core in opposite direction.It is used for blocking high frequency current while it allows direct current & alternating current with low frequency. 90005 90004 90011 Step Down Transformer 90012 90005 90004 90215 90215 90005 90004 A step down transformer is a type of transformer that converts high primary voltage into low secondary voltage. It also converts the low primary current into high secondary current. Step down transformer has Low number of turns in its secondary winding then its primary winding. The conversion depends on the turn ratio of the transformer.90005 90004 90011 Step Up Transformer 90012 90005 90004 90225 90225 90005 90004 The step up transformer converts the low primary voltage into high secondary voltage. It also converts the high primary current into low primary current. It is mostly used for line transmission to decrease the line losses occurring in the transmission line & also to meet the voltage requirement in a circuit. It has low number of primary turns then secondary turns. 90005 90004 90011 Center Tapped Transformer 90012 90005 90004 90235 90235 90005 90004 A center tapped transformer has a tap point in the center of the secondary winding which let us access half the number of turns in the secondary winding.The voltage between the center tap point & any end of the winding is half of that of the full winding. 90005 90004 90011 Transformer with Winding Polarity 90012 90005 90004 90245 90245 90005 90004 The winding polarity in a transformer is denoted by the dot convention. if the current enters the primary dotted terminal, the voltage induced in the secondary dotted terminal will be positive. If the current leaves the primary dotted terminal, the voltage induced in the secondary dotted terminal will be negative.They are mostly used for connecting transformer in parallel to increase their capacity. 90005 90004 90011 Three Winding Transformer 90012 90005 90004 90255 90255 90005 90004 Apart from primary and secondary winding, there is another winding called tertiary winding which is why it is known as three winding transformer. Do not confuse this with 3 phase transformer because 3 phase transformer has only 2 winding i.e. primary & secondary. The tertiary winding is used for providing reactive power where necessary or supplying auxiliary load with different voltage & power levels.90005 90004 90011 Autotransformer 90012 90005 90004 90265 90265 90005 90004 Such type of transformer has only one coil. The turns of the coil are divided in fixed proportion which acts as primary and secondary at the same time. there are no electrical isolation between the coil and the secondary voltage is the result of the self-induction as well as electrical conduction. Small size, lower cost & high efficiency is the main advantage of Autotransformer. 90005 90004 90011 Single phase Autotransformer 90012 90005 90004 90275 90275 90005 90004 This SLD symbol represents a single phase autotransformer.It has only single winding which is used by the same phase conductor. There are two input terminals as well as two output terminals taken from the same coil. They are used for single phase applications. 90005 90004 90011 Variable Autotransformer 90012 90005 90004 90285 90285 90005 90004 A variable autotransformer also known as Variac has a sliding brush that moves continuously across the winding increasing or decreasing the turn ratio of the transformer. The voltage in the secondary varies due to the changing turn ratio.90005 90004 90011 Iron Core Autotransformer 90012 90005 90004 90295 90295 90005 90004 This symbol represents an autotransformer whose winding is wounded around the core made of iron. The iron core increases the magnetic flux which increases the self-induction between the turns. 90005 90004 90011 Three Phase Voltage Transformer 90012 90005 90004 90305 90305 90005 90004 This symbol represents a three phase voltage transformer. It is made up of 6 windings wounded around a single core.There are 3 windings on each side i.e. primary & secondary side. However the windings can be connected in any of these two most common configurations star or delta. 90005 90004 90011 Three Phase Star-Star Connected Transformer 90012 90005 90004 90315 90315 90005 90004 The primary windings & the secondary windings of such 3 phase transformer is connected together in star or wye configuration. Star configuration is a 4 wire 3 phase system where there is a neutral terminal. 90005 90004 90011 3 Phase Transformer — Induction Regulator 90012 90005 90004 90325 90325 90005 90004 Induction regulator is an AC electrical machine similar to an induction motor used for providing a continuous variable voltage.The primary & secondary windings are connected in series. Its output voltage depends on the turn ratio & it can provide continuous voltage ranging from 0 to maximum output voltage. 90005 90004 90011 3 Single Phase Star / Star Connected Transformer 90012 90005 90004 90335 90335 90005 90004 It is the symbol used for 3 single phase transformers whose primary and secondary both are connected in star formation. The star configuration is acquired by combining one end of all three windings to make a neutral point.90005 90004 90011 Three Phase Star Connected Autotransformer 90012 90005 90004 90345 90345 90005 90004 This symbol represents the star configuration is a three phase autotransformer. There are only three windings in a three phase autotransformer that acts as both primary and secondary winding. There may multiple tap points for variable secondary voltage. 90005 90004 90011 3 Phase Star-Delta Connected Transformer 90012 90005 90004 90355 90355 90005 90004 Also known as 3 phase wye-delta (or Star / Delta) transformer is a 3 phase transformer whose primary winding is connected together in star or wye configuration & the secondary winding is connected in delta configuration.It converts the three phase 3 wire system into three phase four wire system 90005 90004 90011 3 Phase Delta-Star Connected Transformer 90012 90005 90004 90365 90365 90005 90004 It is also known as delta-wye transformer & the primary winding of this transformer is connected in delta configuration and the secondary winding is connected in star or wye configuration. It converts the 4 wire (three phase) system into 3 wire (three phase) system. 90005 90004 90011 3 Phase Star-Delta Connected Transformer with Tap Changer 90012 90005 90004 90375 90375 90005 90004 This symbol represent a 3 phase transformer connected in star-delta configuration with a tap changer.The tap changer is used for the regulation of the output voltage by changing the transformer turn ratio. The tap changer switches between many tap points providing variable turn ratios. 90005 90004 90011 3 phase Star / Star Connected Transformer with Connection Points 90012 90005 90004 90385 90385 90005 90004 This is a 3 phase star-star connected transformer with multiple tap points for variable voltage. Each connection point provides fixed output voltage depending on the turn ratio with respect to the primary winding.90005 90004 90011 3 phase star-zig zag Connected Transformer 90012 90005 90004 90395 90395 90005 90004 Such type of 3 phase transformer’s primary winding is connected in wye or star configuration and the secondary winding is connected in zig zag or «interconnected star» configuration. Each phase of the zig zag transformer has two halves. The zig zag configuration provide a neutral for grounding or for supplying a single phase load. 90005 90004 Following is the list of single line transformer symbols.90005 90004 90403 90403 90005 90004 Related Electrical and Electronic Symbols: 90005.90000 Lighting Circuits Connections for Interior Electrical Installations 90001 90002 Introduction To Lighting Circuits 90003 90004 Electrical lines which include 90005 lighting circuits 90006 begin from the main distribution panel of the installation and each line contains three conductors: 90005 phase 90006, 90005 neutral 90006 and 90005 ground 90006. All three conductors reach to the terminal point of each luminaire and if it has a metal chassis the ground should be connected in the appropriate position.90013 90014 90014 Lighting Circuits Connections for Interior Electrical Installations 90004 From each main distribution panel at least two lighting supply lines are leaving, so a failure on one line does not sink the entire installation in the dark. Insulation on the conductors must show the colors 90005 required by the regulations 90006. 90013 90004 The phase conductor must be brown or black, neutral conductor must be light blue and ground conductor must be yellow / green. 90013 90004 90005 To understand the circuit connections we can use various designs, including the following: 90006 90013 90026 90027 Single line diagram 90028 90004 Circuits shown are in the simplified form.These drawings show only the important elements of the lighting circuit and contain information on how to layout, number of the conductors and their cross — section. 90013 90026 90027 Analytical diagram 90028 90004 Which show all the lines that connect the different parts of a circuit. These plans in large scale circuits can lose their figuration. 90013 90026 90027 Operating diagram 90028 90004 Which show in detail the paths of electrical current. This method of design is descriptive and easy to read.90013 90004 90013 90027 1. Simply light circuit 90028 90004 90005 Description: 90006 90013 90004 Connection of one or more luminaire points (Lights) controlled by a 90005 simple switch 90006. This kind of connection is used in almost all 90005 interior electrical installations 90006. 90013 90026 90056 General diagrams 90057 90004 90005 Single line diagram 90006 90013 90062 90062 Simple light circuit — Single line diagram 90004 90005 Analytical diagram 90006 90013 90068 90068 Simply light circuit — Analytical diagram 90004 90013 90056 Operating diagram 90057 90074 90074 Simply light circuit — Operating diagram 90004 90005 Important Note: 90006 90013 90004 In all lighting circuits a ground cable must be installed.Usually the luminaires for residential use belong in the next two categories: 90013 90082 90083 90005 Protection Class I: 90006 The device is grounded. The ground wire (yellow / green) must be connected to the clip marked with ground symbol. 90086 90083 90005 Protection class II: 90006 The device is double insulated and can not be connected to the ground. 90086 90091 90004 Go to back to Content ↑ 90013 90026 90027 2. Selector switch lighting circuit (Comitater) 90028 90004 90005 Description: 90006 90013 90004 A connection of two groups of lamps controlled by a single point.The connection is usually used in 90005 chandeliers 90006. 90013 90026 90056 General diagrams 90057 90004 90005 Single line diagram 90006 90013 90112 90112 Selector switch lighting circuit — Single line diagram 90004 90005 Analytical diagram 90006 90013 90118 90118 Selector switch lighting circuit — Analytical diagram 90004 90005 Important Note: 90006 90013 90004 During the design of various electrical circuits we pay attention to draw them in break mode (OFF), unless there are compelling reasons to the contrary.Above the circuit is ‘90005 closed 90006’, feeding all the lights. 90013 90026 90056 Operating diagram 90057 90131 90131 Selector switch lighting circuit — Operating diagram 90004 Go to back to Content ↑ 90013 90026 90027 3. Two-way switching lighting circuit (Two extreme switches Aller-Retour) 90028 90004 90005 Description: 90006 90013 90004 Control of a lighting circuit from two points (A and B). This type of circuit is used in 90005 hallways 90006, 90005 rooms with two entrances 90006, 90005 stairs 90006, 90005 bedrooms 90006, e.t.c. 90013 90026 90056 General diagrams 90057 90004 90005 Single line diagram 90006 90013 90159 90159 Two-way switching lighting circuit — Single line diagram 90004 90013 90056 Analytical diagram 90057 90004 90005 With rotary switches 90006 90013 90169 90169 Two-way switching lighting circuit — Analytical diagram with rotary switches 90004 90005 With pushbutton switches 90006 90013 90175 90175 Two-way switching ighting circuit — Analytical diagram with pushbutton switches 90056 Operating diagram 90057 90004 90005 With rotary switches 90006 90013 90183 90183 Two-way switching lighting circuit — Operating diagram with rotary switches 90004 90005 With pushbutton switches 90006 90013 90189 90189 Two-way switching lighting circuit — Operating diagram pushbutton switches 90004 Go to back to Content ↑ 90013 90026 90027 4.Switching lighting circuit (Aller-Retour) with two extreme switches and one or more intermediate switches 90028 90004 90005 Description: 90006 90013 90004 Control of a lighting circuit from three or more points. This type of circuit is used in 90005 large rooms 90006, 90005 long corridors 90006, 90005 staircases 90006 and generally in large rooms. 90013 90026 90056 General diagrams 90057 90004 90005 Single line diagram 90006 90013 90215 90215 Switching lighting circuit — Single line diagram 90004 90005 Analytical diagram 90006 90013 90221 90221 Switching lighting circuit — Analytical diagram 90004 90013 90056 Operating diagram 90057 90227 90227 Switching lighting circuit — Operating diagram 90004 Go to back to Content ↑ 90013 90026 90027 5.Lighting circuits with fluorescent tubes 90028 90004 90005 Description: 90006 90013 90238 90083 Circuit of a 40W fluorescent tube, with 40W Ballast and starter. 90086 90083 Circuit with two fluorescent tubes (20W each), with 40W Ballast and two starters (20W each) 90086 90243 90004 The 90005 fluorescent tubes 90006 are used particularly in 90005 factories 90006, 90005 offices 90006, for 90005 decoration 90006 and advertising or promotion of goods. In recent years fluorescent tubes are used in residential installations.90013 90026 90056 General diagrams 90057 90004 90005 Single line diagram 90006 90013 90261 90261 Fluorescent tubes — Single line diagram 90004 90005 Important Note: 90006 90013 90004 In 90005 figure b) 90006 we can add more fluorescent tubes if we want in series but we should also add more starters and a more powerful ballast. 90013 90026 90056 Analitycal diagrams 90057 90274 90274 Fluorescent tubes — Analytical diagram 90004 90013 90056 Operating diagrams 90057 90280 90280 Fluorescent tubes — Operating diagram 90004 90005 Important Notes: 90006 90013 90004 In 90005 figure 2) 90006 If one of the two starters or one of the two lamps stop working, then none of the lamps will eventually function.90013 90004 The metal chassis of the lamp or the ballast’s choke should be grounded. 90005 The fluorescent tubes import reactive power to the grid. 90006 With new European Union directives, mechanical ballasts are repealed and only electronic ballasts (triac) should be used, which limit the reactive power. 90013 90004 The starter and the capacitor are abolished and we have direct ignition of the lamp. 90013 90004 Go to back to Content ↑ 90013 .90000 Understanding Substation Single Line Diagrams and IEC 61850 Process Bus (Depicting Relay Circuits) 90001 90002 Single Line Diagram (SLD) 90003 90004 The single line diagram (SLD) is the most basic of the set of diagrams that are used to document the electrical functionality of the substation. Its emphasis is on communicating the functions of the power equipment and the associated protection and control system. 90005 90006 Figure 1 — Protection engineer setting ABB’s relays in power substation (photo credit:.elettronews.com) 90004 Details about connection and physical location are not as important unless they serve the purpose of communicating function. For example, in Figure 10, the CT polarity marks indicate the direction of the current that a protective element is oriented to, thereby implying a function. 90005 90004 Symbols very similar to Figure 2 and Figure 3 can be seen in Figure 10 which is an example of an SLD. 90005 90004 The challenging task behind the SLD is to include all the necessary data while keeping the diagram easy to read.Therefore the single line may rely on non-intuitive symbology to represent devices since communicating function is so important. 90005 90013 90013 Figure 2 — Examples of Symbols Used on One Line Diagrams 90004 Typically, single line or one line diagrams are used to document the configuration of the electrical high voltage circuit of a substation. 90005 90004 Symbols are used to depict the 90018 high voltage equipment 90019 including: transformers, generators, circuit breakers, fuse, air break switches, reactors, capacitors, instrument transformers, and other electrical equipment.The connections between these pieces of electrical power equipment are shown by solid lines. 90005 90004 On these diagrams the three phase equipment and connections are shown with a single line, thus the basis for the diagram name. Single phase equipment may have the same symbol as a three phase device but will be specifically designated with the phase to which it is connected. 90005 90004 Since three phase devices can be connected in a 90018 delta, phase to phase connection, or a wye, phase to neutral connection 90019, symbols are included that indicate the type of connection.This can be a vector representation of the connection or may be indicated by the winding symbol itself. 90005 90027 90027 Figure 3 — Three Phase Connection in a Single Line Diagram 90004 In some cases a key or basic substation SLD will be used to show just the electrical configuration of the high voltage equipment in the substation. The equipment is shown in the basic physical arrangement but when there are difficulties in showing the equipment in the correct physical orientation and showing the equipment in the correct electrical configuration then the correct electrical configuration is given priority.90005 90004 Beyond the documentation of the high voltage equipment’s configuration, typically some of the 90018 control and protection systems 90019 are shown on the SLD in a basic form. The most common additional system to be depicted on the SLDs are the current and voltage transformer circuits. 90005 90004 Both the primary and the secondary of these circuits are shown. In both cases only half of the secondary circuit is shown. 90005 90004 The polarity or delivery half of the circuits for relay operation, not the return circuits, are shown.The secondary circuits for the current transformers are typically shown with solid lines between the devices. 90005 90004 To distinguish difference between the lines for the high voltage circuit and the current transformer circuit, 90018 the high voltage circuit is shown with a wider solid line than the current transformer circuit 90019. The devices connected to the current and voltage transformer circuits are often shown with a circle large enough to contain a function number or acronym. 90005 90004 The function numbers and acronyms are listed in the IEEE standard C37.2-2008. 90005 Contents: 90045 90046 Single Line Diagrams and IEC 61850 Process Bus 90047 90004 Application of IEC 61850 process bus requires a rethinking of 90018 how relay circuits are to be shown on an SLD 90019. The merging unit (90018 MU 90019) in a process bus implementation takes analog inputs of voltage and current and digital inputs and converts them to IEC 61850 protocol. 90005 90004 The output is a data stream over a fiber optic connection either to data management equipment or directly to IEDs performing a protection function.In this case, the physical connections to the MU shown on an SLD are unlikely to convey any functional information because the fiber optic connection can carry data concerning voltage, current or digital inputs to the MU. 90005 90056 90004 90018 Knowing what CTs and VTs are feeding an IED 90019 can help indicate the protective functions it is performing. 90005 90061 90004 90063 90064 90005 90004 With an MU, you can only tell the set of data that may be feeding the IED, not what data it is using.The protective functions that the IED is performing will not be obvious from the connection alone. 90005 90004 What follows are two examples of how to depict the process bus on SLDs. 90005 90004 Go back to contents ↑ 90005 90045 90073 Single Line Process Bus Example A 90074 90004 Previously, there was a one-to-one relationship between the analog measurement (CT or VT) and the input to the IED. Therefore simply showing 90018 a connection from a CT to an IED 90019 was not only a representation of the physical but also the functional, whatever functions the IED performed had to be based on the analog input.90005 Now, an MU can have multiple analog signals input to it and then have a single physical output — a fiber optic cable. 90004 So a simple way of showing this is to be consistent with the physical representation, namely CT and VT connections are shown going to the MU but to add text to the fiber input to the IED so the analog input can be followed back to the MU so the function of the IED can be more obvious. 90005 90081 90081 Figure 5 — Example A of Merging Unit on Single Line 90004 An example of this approach is shown in Figure 5.The MU is labeled as 90018 MC # 2 90019 and the inputs shown are 90018 phase current (CP), ground current (CG), and phase voltage (VP) 90019. The IED labeled as 90018 6CB32 90019 is using VP while 90018 3T4 90019 is using CP, CG and VP. 90005 90004 Go back to contents ↑ 90005 90045 90073 Single Line Process Bus Example B 90074 90004 Another proposal for representation of the process bus on the SLD is 90018 to depict the MU as an optical auxiliary transformer 90019. This retains the practice of showing a one-to-one relationship between analog measurement and the input to the IED.90005 90004 So the 90018 function of communicating the analog voltage or current data to protective relays 90019 could be shown as in Figure 6. 90005 90004 These symbols would reflect the physical connection to the current and voltage inputs but would depict the output as data to the subscribing IEDs. Therefore one MU may have both a voltage and current input with output to numerous IEDs. The input to each of these IEDs would be shown separately for each current or voltage. 90005 90108 90108 Figure 6 — Symbols for Current and Voltage Output of a Merging Unit and Example B of Current Data Connection to IEDs 90004 Figure 6 shows 90018 the current data output from an merging unit (MU).90019 90005 90004 If this is interpreted as a physical depiction it would seem that there were numerous physical connections when in fact there may be a single fiber connection from the MU to the control building. 90005 90004 In addition, because it is current data it is not delivered serially to the IEDs as it would if it were a CT, rather, the data is delivered in parallel to the IEDs. Labeling would allow the association of the function to the correct MU. 90005 90004 In Figure 6, 90018 the MU has multiple current and / or voltage inputs 90019 therefore labeling will need to address this.Here, it is current element 1 (C1) of merging unit C12 (MUC12) that is being used. 90005 90004 A more detailed representation of the physical connections from the CTs and VTs to the MUs would be shown on the AC schematics and the physical connection from the MU to the IEDs could be show on a process bus architecture drawing. 90005 90004 Go back to contents ↑ 90005 90045 90046 Control Functions on the Single Line Diagram 90047 90004 It has been common to show the function of the basic protection circuits and sometimes the control circuits on the SLD 90018 by connecting the protective relay circles that enable other devices with dashed lines 90019.90005 These are the circuits of the response actions, trip and close, which are automatically performed by the protective relays. 90004 An arrow at the receiving end of the dashed lines indicates the direction of the action. The devices that trip or close the high voltage fault interrupting device have dashed lines to the symbols for those devices. 90005 90004 These «control lines» can be seen in Figure 4 90018 pointing at the circuit breakers in the drawing 90019. This method of depicting the relay logic on the SLD has limitations.90005 90004 The conjunction of two control lines typically depict an OR junction, meaning that either incoming action would result in the same resulting action. 90005 90141 90141 Figure 4 — Example A of a Single Line Diagram 90004 The depiction of the logic requiring multiple control actions to be enabled at the same time to accomplish a resulting action, an AND gate, is difficult to depict with this type of documentation. In spite of the shortcoming of this method of logic depiction it has been used for many years and continues to be used.90005 90004 The advent of user modified control logic in microprocessor based relays challenges the application of this type of relay logic depiction on SLDs. 90005 90004 When the logic of the protection or control circuit is no longer limited to the results of wiring individual relay functions together but is the composite of the user defined logic internal to the relay devices and the external wiring between devices the limitation of the dashed lines to depict the overall protection circuit logic has become unacceptable for many users.90005 90004 The same evolution in protective relay logic also increased the importance of having a 90018 method of detecting the basic overall logic on one diagram 90019. 90005 90004 Prior to the user defined logic in microprocessor based relays, the control schematic provided this overall logic diagram because the logic was created by the wiring of individual functions together. 90005 90056 90004 With the advent of the microprocessor based relay, 90018 one output contact can be the composite result of the operation of multiple measuring devices combined with timer and multiple conditional situations 90019.None of this internal complex logic is shown on the typical control schematic. 90005 90061 90004 As a result of these two factors, the limitations of the legacy documentation system and the need to document the internal relay logic along with the external logic, has driven many utilities to change the way that protection relay logic is depicted on the SLDs. 90005 90163 90163 Figure 7 — Diagram Comparison of Logic Symbols 90004 One method that has been adopted by some utilities is to depict the basic protection relay logic on the SLD using the traditional Boolean logic symbols or some variation of these symbols.90005 90004 90018 By using Boolean logic, more complex logic can be depicted than what could be depicted using the dashed line with the arrows 90019 and both logic internal and external to the programmable relays can be shown on the same diagram. To facilitate the SLD being understandable by a larger audience at least one utility has adopted symbols used on some generating plants drawings. 90005 90004 These symbols and the more traditional symbols are shown in Figure 7 above. 90005 90004 Figure 8 shows a section of a substation SLD using logic symbols to portray the way the protection and control circuits for the tripping and closing of a circuit breaker are configured.90005 90175 90175 Figure 8 — Section from Substation Single Line (click to expand) 90004 90018 The circuit breaker has two trip coils so the logic for each is shown separately. 90019 Both the control logic that is accomplished by inter-device wiring and logic that is accomplish by the custom programming of microprocessor based relays are shown on the same diagram. 90005 90004 Referring to Figure 8 above, the logic inside the dashed box labeled 90018 (1M63) 62BF5 90019 is custom programmed logic whereas all of the other logic is accomplished with inter-device wiring.The logic shown for device (1M63) 62BF5 is a simplification of the complete logic. 90005 The complete logic for this device can be shown on the control schematic for the breaker failure protection. It is important to link the inputs and outputs of this device to the external logic shown on the SLD. There is no local area network (LAN) used for the protection and control circuits at the substation shown in Figure 8. 90004 If there was a LAN the protection and control logic accomplished with signals communicated over the LAN are shown on the same diagram.90005 90187 90187 Figure 10 — Line Relay Symbol for Substation Single Line Diagram (click to expand) 90004 The more complex logic like that used in a transmission line pilot scheme are shown in symbols like Figure 9. Figure 9 is the logic for a permissive over reaching transfer trip scheme using relay to relay digital communication. 90005 90004 To simplify the logic for the SLD some of the details of the logic are left out. Some examples of that simplification are the showing of just Zone types and not the individual elements that are combined by logic to detect faults in a Zone and the absence of the timing functions involved in the echo back keying of the permissive trip signal circuit.90005 90004 With the logic for the protection and control circuits in addition to the primary power circuits, and the current and voltage circuits being shown on the SLD. The SLD can be used to understand the systems being applied in the substation. 90005 90056 90004 The SLD is also a critical link 90018 between the schematic diagrams and the relay settings documents in troubleshooting protection and control circuits 90019. 90005 90061 90201 90201 Figure 10 — Example B of Single Line Diagram (click to expand) 90004 Even though there are commonalities between all single diagrams, any two SLDs from different organizations can look very different.Figure 10 is another example of an SLD but it emphasizes the digital inputs and outputs to each relay along with the use of different texts and additional symbols such as the trip and close descriptions. 90005 90004 But even with these differences, single line diagrams summarize both the power system to be protected and the controls that will operate the power system. 90005 90056 90004 The next level of detail of power system relaying is found in the AC and DC schematics. 90018 The AC schematics detail the power system being protected and how it is being measured.The DC schematics detail the controls that operate the power system. 90019 90005 90061 90004 Go back to contents ↑ 90005 90004 90216 90018 Reference // 90019 Schematic Representation of Power System Relaying by Power System Relaying Committee IEEE Power Engineering Society 90219 90005 .