Electrical diagrams1

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ElectricalDiagrams

General

Single wire diagrams

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AGENDA

GENERAL

SINGLE WIRE DIAGRAMS

FUNCTIONAL DIAGRAMS

WIRING DIAGRAMS

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AGENDA

GENERAL


FUNCTIONAL DIAGRAMS

WIRING DIAGRAMS

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General An electric diagram is a representation of how the different parts of

a network, an installation, or a device (or group of devices) are connected and related among them.

The diagrams are classified in:

Single-wire: These diagrams show the path of current circulation, as well as the main elements of the power system (lines, buses, transformers, circuit breakers, disconnectors, surge arresters, generator, etc.). They show solely one phase of the circuit in balanced systems.

Multiwire: They are more complete than single-wire diagrams, since they present the information of every phase of the circuit.

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Functional: They also show the connections of the circuit breakers (always in open position), disconnectors (also in open position), AC and DC circuits without voltage, unexcited auxiliary relays, open AC and DC circuit breakers, signal and drive switches, etc.

Wiring: There are two kinds of wiring diagrams:

Interconnection among devices.

Internal interconnection of devices.

When elaborating a diagram, care should be taken to make it as easy to understand as possible, avoiding information that could lead to confusion.

General

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All collections of functional diagrams must show the conditions of representation and nomenclature of terminals, as following:

Conditions of representation of diagrams: Open circuit breakers. Unloaded springs.

Open disconnectors.

Unloaded AC and DC circuits.

Unexcited auxiliary relays.

Open AC and DC automatic circuit breakers.

Signal and drive switches in position “rest after opening”.

Terminal nomenclature Position switchboard, frontal.

Position switchboard, back.

Other switchboards.

Outdoors devices and boxes.

General

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AGENDA

GENERAL


Introduction

Symbols

Examples

Single wire diagrams of transformer substations

General diagrams and their interpretation

FUNCTIONAL DIAGRAMS

WIRING DIAGRAMS

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Single-wire diagrams It is the representation in solely one line of

two or more conductors.

Hence, it might represent:

Circuits of one-phase or multi-phase systems

Conductors with the same layout.

The line that symbolizes the conductors of a sole circuit will be crossed by as many diagonal lines as phases are in the circuit. This criterion is not applied to high voltage installations.

The single-wire diagrams can be: General

Simplified

The difference between them resides in the level of detail, minor in the seconds.

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Single-wire diagrams

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AGENDA

GENERAL


Introduction

Symbols

Examples



FUNCTIONAL DIAGRAMS

WIRING DIAGRAMS

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Symbols

Opened contact

Closed contact

Disconnector 89

Automatic circuit breaker 52

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Symbols Current transformer

Current transformer with marked polarity

One-phase voltage transformer

Voltage transformer with marked polarity

One-phase voltage transformer

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Symbols

Thermal relay [49]

Hour counter

Ammeter

Voltmeter

Magneto-thermal breaker [98]

Auxiliary relay coil

Tilting auxiliary relay

Time-delay relay coil

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Symbols

Integrator

Wattmeter

Active energy counter

Varmeter

Reactive energy counter

Synchronoscope

Display

Frequency meter

Current converter

Voltage converter

Active power converter

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Symbols

Three-winding three-phase transformer

Three-winding three-phase transformer

Three-phase transformer of multiple taps with on-load tap changer

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Standard device function number (IEEE C37.2)

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AGENDA

GENERAL


Introduction

Symbols

Examples



FUNCTIONAL DIAGRAMS

WIRING DIAGRAMS

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Examples. Low voltage motor supply The following diagram shows the installation of

a three-phase motor, with tripolar circuit breaker and three protection fuses.

The representative conductor is crossed by three diagonal lines, showing that this is a three-phase circuit.

The terminals of the fuses of each phase are indicated (1-2, 3-4 and 5-6), as well as those of the poles of each phase of the circuit breaker.

There had not been indicated the characteristics of the installation, such as rated voltage, conductors section, motor power, or fuses and circuit breaker characteristics.

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Examples. Low voltage motor supply The single-wire diagrams are

inadequate in diagrams of motor installation when they have the possibility of turn inverter, stator-resistances starter, speed variation, etc.

In these cases, the multiwire diagram is recommended, as shown in Fig.

It can be appreciated the circuit breaker Q1, two contactors KM1 and KM2 to invert the direction of rotation, a contactor KM11 to short-circuit the resistances and the three-phase motor.

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Examples. Outdoors MV transformation centre

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Examples. Indoors MV transformation centre

1. Transformer bay.2. Protection bay.3. Incoming feeder bay.4. Outgoing feeder bay.5. Low voltage switchboard.

MAIN BUS

OUTGOING FEEDERS LOW VOLTAGE SWITCHBOARD

CIRCUIT BREAKER

TRIPOLAR DISCONNECTOR

GROUNDING

TRANSFORMER

FUSE

MULTIPOLAR CIRCUIT BREAKER

TERMINAL

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AGENDA

GENERAL


Introduction

Symbols

Examples



FUNCTIONAL DIAGRAMS

WIRING DIAGRAMS

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Single-wire diagrams of transformer substations

Symbols of circuit breakers

Circuit breaker of the manufacturer AEG,

rated voltage 72.5 kV,

rated current 1250 A

breaking capacity of 25 kA.

Besides, it is indicated as the circuit breaker number 5 of the 72.5 kV switchyard.

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SYMBOL LABEL

Double side-break disconnectors

Centre-break disconnectors

Pantograph disconnectors

General symbol (unipolar disconnector)

Symbols of disconnectors

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Two disconnectors are pictured: 89-5-1 and 89-5-2.

Both have the same characteristics:

Model: MESA "SGC".

Rated voltage: 72.5 kV.

Rated current: 1250 A.

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Symbol of surge arresters

Three Siemens surge arresters,

model EP2060-2PN

rated voltage 60 kV,

star-connected and grounded.

It has not been indicated the model of the installed discharge counter.

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Symbols of power transformers

Symbols of autotransformers

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The specifications that should appear in the diagrams for these equipments are:

The transformers are signalled by the letter T followed by the number that indicates their order inside the substation where they are installed.

The autotransformers are signalled by the letters AT followed by the number that indicates their order inside the substation where they are installed.

Power expressed in MVA or kVA.

Connection group.

Rated voltage of every winding.

Indication of the grounding connection.

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Transformer with: rated voltages 66 kV and 50

kV in the high voltage side

22 kV in the secondary

on-load tap changer, as indicated by the arrow that crosses the primary winding.

The voltage of operation is indicated by underlining.

In the transformers with no-load tap changer the following symbol is utilised:

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Current transformer symbols in accordance to different standards

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Current transformer symbols

Fig. 20

Three transformers, manufacturer

Arteche, model CXG-72, transforma-

tion ratio, delta-connected.

Fig. 21

Three current transformers, bushing

type BM, mounted inside a circuit

breaker.

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Voltage transformer symbols

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Voltage transformer symbols

Fig. 25

Three one-phase voltage

transformers removable

type with double secondary

winding:

- One star-connected.

- The other connected in

open delta.

- The primary is star-

connected and pro-

tected with fuses.

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Capacitive voltage divider symbol

The diagram also shows the equipment of the drainage coil, connected in parallel with a discharger and a disconnector, so when the drainage coil has to be disconnected the ground reference in the capacitive divider is not lost.

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Capacitor battery

Each capacitor has individual protection (fuses).

The battery has an installed power of 3600 kVAr, is star-connected and fed by an underground cable with a rated voltage of 22/ kV.

It also includes three voltage transformers for measurement and protection.

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The measurement devices in any single-wire diagram are represented by a circle, including their correspondent symbol:

Voltmeter

Ammeter

Wattmeter

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The protection relays in any single-wire diagram are represented by a circle, including their correspondent number, according to standard IEEE C37.2-1996:

Synchronism-check device

Distance relay

Differential protective relay

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SW diagrams is the simplified description of the connections among the different elements in a substation

It is defined by : Nº of transformers

Nº source and feeder lines

Buses configuration

Switching elements

220 kV

L1

EB

L2 L3 L4 T1 T2 T3

MT

10L

- - - EB1

10L

- - - EB2

10L

- - -

50MVA 50MVA 50MVA

PB


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The most used bus bar arrangements are: Single bus

Double bus

Multiple bus

Ring bus

Every bay is composed by several elements:

When the breakers are detachable it is not necessary to install isolating disconnectors

IsolatingDisconnector

By- pass Disconnector(optional)

Breaker


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The simplest arrangement is single bus

Advantages: Simple and easy operation

Very easy interconnection wiring

Reduced cost

Disadvantages: A single bus failure implies substation

blackout

Breaker maintenance implies bay outage (by-pass)

ST expansion needs de-energizing

Reliability can be improved splitting the bus and/or adding by pass disconnectors for maintenance purposes

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.......

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......


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“H” Diagram

Particular case of split single bus with tie breaker or disconnector. Very used in distribution or customer substations

Two possibilities, H3 (3 breaker) or H4 (4 breaker)

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......

......

......


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The double bus conf. has several possibilities: One breaker, two disconnectors

Breaker and a half

Two breakers

Advantages: Flexibility for circuits clustering

Bus maintenance without de-energizing

Disadvantages: More area needed. Higher cost

Breaker failure implies circuit outage

Reliability is improved with bus tie breaker: Load transfer

Line breaker outage

.........

.........


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Breaker and a half: Solves the problem of breaker failure

It complicates switching and protection

Higher cost and area needs

Two breakers: Greater flexibility

Greater reliability

Higher cost and area needs

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............


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The ring arrangement rises reliability and flexibility

It uses the same number of breakers than circuits

Advantages: Breaker disconnection does not imply outage

Two sources for every circuit

Disadvantages: More complicated operation

More complex protections

Expansion limited


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In planning an electrical substation or switchyard facility, one should consider major parameters as discussed, Reliability

Cost

Available area

Most used arrangements: Transmission substation, double bus generally

Distribution substations,

Single bus in HV (H3- H4)

Double bus in MV

Customer substation

Single bus in HV (H3, H4)


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AGENDA

GENERAL


Introduction

Symbols

Examples



FUNCTIONAL DIAGRAMS

WIRING DIAGRAMS

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In these diagrams, besides the power circuits, the circuits of protection and measurement are also included.

The characteristics of all represented devices (transformers, capacitor batteries, etc.) shall be indicated, including protection relays and automatisms.

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General diagrams. Transformer bay

The associated circuit breaker, 52-1, has the following characteristics: Manufacturer: Sprecher.

Model: HPF-409H

Rated voltage: 72.5 kV.

Rated current: 1600 A.

Breaking capacity: 20 kA.

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The circuit breaker receives tripping order from the following relays: 51: Direct order.

86: Receives tripping order from the operation of the relays:

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86: Receives tripping order from the operation of the relays: 87: Differential.

63B: Buchholz relay of pressure of the liquid of the transformer. Provides alarm and tripping for the circuit breaker 52-1 through the relay 86 and by means of its auxiliary 63BX.

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86: Receives tripping order from the operation of the relays: 51NX: Actuates as a consequence of the operation of the relay 51N of neutral overcurrent, also providing

the corresponding alarm. The 51N relay is fed by a current transformer type BR, with ratio 300/5 A, power 15 VA and class S20 that trips over circuit breaker 52-6.

50: Instantaneous overcurrent relays fed by current transformers type BR, with ratio 300/5 A, power 15 VA and class S20.

63N: Pressure indicator relay of the liquid where the reactance TZ-1 is immersed. This relay 63N trips the relay 86 by means of its auxiliary 63NX, raising the corresponding alarm by the relay 63AX.

26: Thermal relay of overtemperature indication of the liquid where the reactance TZ-1 is immersed. It provides alarm indication but no tripping order over the circuit breaker.

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The secondary windings of the voltage transformers are protected by automatic circuit breakers 98. The 98 in the star-connected secondary winding of voltage 0.11/ kV activates an auxiliary relay 98X. From this winding, the bus voltage measurement is obtained by means of a voltmeter of 0-75 kV connected through a voltage switch CV. Three fuses of 2 A had been installed to protect the voltmeter.

The diagram also represents a frequency automatism by the utilization of a frequency relay 81 that by means of the auxiliary relay 81X causes the automatic closing of the general circuit breakers of 22 kV.

However, the relay 81Y, auxiliary of 81, is the one to trip the general circuit breakers of 22 kV. The frequency automatism is activated by the operation of the switch 69F.

There is installed as well an automatism for the automatic reposition of voltage, for which a relay 27B has been installed, fed by the star-connected secondary winding of voltage 0.11/ kV. The auxiliary relays 27BX, 94-1 and 94-2 of the relay 27B trip the lines L-1 and L-2.

General diagrams. Bus voltage transformer

Electrical diagrams1

Engineering

Transcript of Electrical diagrams1