DE2925109A1 - METHOD FOR SHUTDING OFF SHORT CIRCUIT CURRENTS IN ELECTRIC HIGH VOLTAGE SYSTEMS AND DEVICE FOR CARRYING OUT THIS - Google Patents

Description

Vsesojuznyj Gosudarstvennyj proektno-izyskatelskij i nautschno-issledovatelskij institute energeticheskich sistem i elektritscheskich setej

Moscow / USSR

P 79 418-E-61 June 21, 1979 L / Kdg

PROCEDURE FOR LOST VuW KUKZSCHLUuoTROMEH IN HJLaKTRl öüHEW HUttSPAMflUNGbAWLAGE «AND FACILITIES TO DjüSSJSW IMPLEMENTATION

The present invention relates to electrical engineering, in particular to a method for switching off short-circuit currents in elokbrLochen ^ ₀ chspannungsanlagen and a device to the "s implementation.

The invention can be used in switchgears designed for 10OkV and above with a rigidly earthed neutral conductor and for switching off electrical high-voltage systems in an alternating current network in the event of a short circuit with the aid of relay protection and automatic systems. be used

909881/0823

BATH ORIGINAL

-Zf-

A method for switching off short-circuit currents is known [in high-voltage electrical equipment which the application Sound switching devices enables which (hereinafter referred to as group switch) intended to switch off the load and work in the currentless pause after the short-circuit current has been switched off, which is controlled by a switching device (main power switch) is made. The short-circuit current is switched off as follows: in the event of a short-circuit the main circuit breaker switched off, whereupon within the duration of the de-energized pause the group switch la circuit of a disturbed feeder responds.

The high-voltage electrical systems in which she knew Method used contain a main circuit breaker and one with in each circuit of a branch this series-connected group switch, which by similar electrical parallel circuits of other branches (see e.g. "Power supply part of the electricity works and substations", Wasiljew A. A., Verlag "Energie", Moscow, 1972, p.180) bridged s ind

According to the known method, a slowed down through one
run by the relay protection of the damaged network element to turn off the command delivered to the switch, which overall increases the time required to eliminate a severe short circuit of high amperage.

It is a device for switching off short-circuit currents known in power transmission lines, which when on the Lei-r The short circuit caused by the device is switched off at the same time

909881/0823

BATH ORIGINAL

all switches of the disturbed power transmission line (see e.g. "Regulations for heat protection. High-frequency current direction comparison protection of lines with voltages from 110 to 530 kV ", Verlag" Energie ", Moscow, 1972). When a short circuit occurs in a network element, the currents of the network limit the breaking capacity of one of the switches in this element exceed, a command is formed by the protective relay unit in order to switch off all switches of this element at the same time Switches with insufficient breaking capacity are commutated, which leads to the failure of this switch. The Failure the latter causes the automatic devices on the property to be triggered, e.g. the triggering of a reserve device for the failure of a switch), so that a large number is switched off by branches, which the functionality of the power supply unit as a whole, which is why it is necessary to use the switch with insufficient breaking capacity to replace

Here you can in the known device switches with insufficient breaking not use, that solehe, die'für da3 shutdown of Gesamtkurzschlußstromsglicht \ are designed.

Discloses a device for leading Gruppenfeelluiqg a power supply system which includes a relay protection UNAE a switch of the branch as well as protection from voreilea- ά "χ Wiricunc aufweist3durch the tw? Disconnection

.'- --J ^! '-> i J "J' Jl .;" i

A short circuit is blocked, the current of which has the breaking capacity of the switch exceeds. Breaking capacity is an ability to break the circuit at a given Interrupt size of the short-circuit current, which is about the switch flows, understood.

The disadvantage of the technical solution consists in a possible slowing down of the flow of the relay protection of the disturbed network element to the deactivation of it Switch supplied command, which on the whole extends the time it takes to eliminate a serious short circuit large amperage is required.

The invention lie ^ t the object ', ^to provide a method for switching off short circuit currents in high voltage electrical equipment, and means for its implementation, can be used in Donon switch with unzurechendem breaking.

one

The se object is achieved in that the method for switching off short-circuit currents in electrical High-voltage systems, which in the circuit of each branch have a main circuit breaker and one with this in Series connected additional circuit breakers by similar electrical parallel circuits of the other branches are bridged, included, br> i. dom man in the presence

its a short circuit in one of the circuits

of the feeder the main circuit breaker and the additional circuit breaker of the same circuit, according to the invention of the additional power switch before switching off

S 0 B 8 B 1/0 -J: '

DAD

of the main circuit breaker of the same circuit of the feeder is switched off to the short circuit current over the lifting circuit of the feeder to redistribute and the short-circuit current direction to change so that the short-circuit current over the Main circuit breaker flows through which the short-circu »- eent circuit of the feeder is switched off. ■ ^ an advantageous! Facility

sur switching off a short-circuit current that affects each circuit main circuit breaker or additional circuit breaker assigned to the feeder, a protective relay unit and a « Intermediate relay unit, the latter two being. with power transformers are connected in series, as well as each to the

Intermediate relay unit connected control parts for the main controller or · Additional circuit breaker contains, according to the invention with a Current relay provided, its winding between the current transformers and the protection relay unit is connected and its break contact between the intermediate relay unit and the control section of the additional circuit breaker.

The »wide input of the control section of the additional circuit breaker can be connected to a source for control · direct current via a normally open contact of the current relay.

if.
It is useful to use the output of the intermediate relay unit

with the input of the control section of the main circuit breaker both via the closing contact of the current relay and via

909881/0823

BATH ORIGINAL

a series chain from another closing contact of the current relay and a delay element is connected.

The device can also have a unit for stepping up the response of the auxiliary circuit breaker on the input side to the output of ^ö chutzrelaiseinheit and output side connected through the closing contact of the ^ romrelais to the input of the control part of the auxiliary circuit-breaker ·

The device according to the invention ensures high operational safety of the electrical system using devices of a lighter design than additional circuit breakers and with

η. ,
the rapidity achieved in the issuing of the «elais-

from

protection of the object to turn off its switch supplied Command.

The invention is described below with reference to embodiments

n
examples with reference to the accompanying drawings

explained in more detail. It shows:

1 shows a basic circuit diagram for switching off a

Short circuit current according to the invention;

one
Fig. ?, a circuit device according to the invention but

Disconnection of short-circuit currents;

3 shows another circuit of the same device with a unit to force the response.

The inventive method for switching off short-circuit currents is considered using the example of an electrical high-voltage system, the circuits 1, 2, 3, 4, 5 and 6

909881/0823

"BAD. ORIGINAL

(Pig.1) of a feeder, which via busbars 7 and 8. Lines 1 to 6 will be switched off through main circuit breakers 9 and 10, 11 and 12, 13 and 14 and Additional circuit breaker 15 »16.17. The additional circuit breaker are in communication with the main circuit breakers 9-14 as shown in Fig. the circuits 1,2 are the switches 9 »10 and 15, the circuits

and
3,4 the switches 11,12 and 16, the circuits 5,6 the

Switches 13 »14 and 17 assigned.

As switches 15 to 17 such switches are used which are suitable for the rated current in a corresponding To interrupt the circuit.

In the event of a short circuit in one of the circuits, e.g. in circuit 1, switch 15 is switched off first and the short-circuit current is redistributed over two shunt circuits consisting of switches 11, 16 and 12 and the switches 13,17 and 14 insist, whereupon the main circuit breaker 9 is switched off. Similarly, when a short circuit occurs in the circuit 3, the switch 16 is switched off and the short-circuit current through the shunt circuits consisting of switches 9, 15 and 10 and switches 13, 17 and 14 redistributed whereupon the main circuit breaker 11 responds.

In Fig. 2 and 3, the retention-like embodiments of devices for switching off short-circuit currents for only one circuit of the branch shown; it is a circuit 1 with associated switches for consideration

809881/0823

9 and 15 assumed, which is shunted with the circuit 2 and connected to a power supply system 18. Current transformers 19 and 20 (Fig. 2), which are arranged in three phases of the switches 15 and 9, are connected for the sum of the currents of the circuit 1 to be protected and connected to a ** series chain, which consists of a current relay 21 and a Protective relay unit 22 exists. The output of protective relay unit 22 is connected to the input of an intermediate relay unit 23. The output of the latter is connected to the input of the control unit 25 of a load switch 15 via a closing contact 24 of the current relay, and a source for oLüuüi · current is connected to the other input via a further closing contact 26 of the current relay 21. Between the output of the unit 23 and the input of a control part 28 of the power switch 9, there are two parallel circuits, one of which is one of a normally open contact 29 and the relay 21 and the other from the ^fi eihenkette an opening contact 30, the ütromrelais 21and a delay element 31st The short circuit in the line is denoted by 32 · The work of the device is for the real case of a

on
Inequality of the switch-off time of the switches 15 and 9 explained.

for The switch-off time of the load switch 15 is. Example same

100 ms and that of switch 9 is assumed to be 80 ma. The protective relay unit 22 and the unit 23 speak in the range of 4-0 ms in the event of short circuits only within the

909881/0823

circuit 1. The current relay 21 responds with a time of at most 5 ^{> J} i ^ß 10 ms in the event of short circuits in the direction of the circuit 1 to be protected and is set in such a way that its sensitivity to short circuits over the entire distance of the circuit 1 to be protected is sufficient.

Upon the occurrence of a short circuit 32 in the protected circuit 1, the relay 21 and the S _c hutzrelaiseinheit 22 is responsive, the contact 26 of the relay 21 is closed and applied to the input of the control part 25 of the switch 15 "Plus" the DC power source 27 is · By the control part 25 is hereby formed a command for switching off the switch 15. As a result, the switch 15 switches off.

When the current relay 21 responds, its contact 29 is closed, so that the unit 23 via the contact 29 and the control part 28 receives a signal to switch off the circuit breaker 9.

The total switch-off _{time of the circuit breaker 9 t,} which is counted from the time the short circuit 32 occurs, is for the. consider the th case approximately 120 ms and comprises the response time of the units 22 and 23 and the. own switch-off time of switch 9

909881/0823

The current path lying between the unit 23 and the control part 28 is through the opening contact 30 of the current relay 21 interrupted. The current path between the unit 23 and the Control part 25 is through the opening contact 24 of the Stroiarelais also interrupted. In the overall result, the load switch is 15 / faster than the circuit breaker 9 ^ um

in -A

a time of at least 10 ms /, i.e. less than half a s'ior Industrial frequency period, switched off. The switch-off conditions of the circuit breaker 15 prove to be light because it / practically does not pass the short-circuit current ^ due to its shun

^^ 7

by the circuit breaker 9 / switches off. At the moment the complete contact separation of the switch 15 proves

as

the resistance between its contacts is incomparably higher than the resistance of the parallel circuit of the closed Switch 9 iso that practical over the last ren the entire short-circuit current flows. The switch 9 is later as the switch commutates and switches the overall short-circuit current from the energy supply system 18.

In the device is a possible failure of the current relay 21 to respond to the requirements with regard to the Be made responsive, z.ü. in the event of a short circuit in the Point 32 taken into account. If the current relay 21 fails,

ßme

his contacts not rearranged, so that his / her closed StateN due to weight response of the atrom relay 21 (located opening contact 24 from the unit 23 a signal for switching off the switch 15 via the desewil control unit 25 arrives, the switch 15 in a time of not

909881/0823

ORIGINAL INSPECTED

is switched off less than 140 ms after the occurrence of the short circuit in point 32. In this case, the circuit between the ^# Tlus "of the direct current source 27 and the control part 25 is opened. The command for switching off the switching

h ters 9 comes from unit 23 via the closed chain, from the opening contact 30, the delay element 31 the control part 28 of the switch 9 consists. This switch 9 is in a time of not less than 150 ms after

Occurrence of the short circuit, i.e. later than the container In the event of such a sequence of steps to switch off, switch 15 switched off without practically commutating the short-circuit current, such as it was stated above. The total short-circuit current is through the switch 9 in 10 ms after switching off of switch 15 switched off. In such a working sequence of the switch, the delay element 31 must have a setting time have the 'the difference in their own switch-off times of switches 15 and 9, taking into account a Reserve time of 10 ms (half the period of the industrial frequency), i.e. about 30 ms ^ equals ^

The current path between the unit 23 and the control part 28 is opened by means of the contact 29, which is necessary because the command for switching off the switch 15 must arrive with a delay via the parallel circuit. The presence of the opening contact 24 is due to the fact ^that switching off the load switch 15 in the event of a short circuit may not be permitted if the unit 22 and the current relay 21 have responded, but the opening contact 26 of this relay has failed and the DC-

909881/0823

power source 27 'is connected to the control part 25 ") 1 117-done' ^/

no command at all for switching off the switch 15 because its leading switch-off (compared to the switch 9) is not prepared by the entire circuit arrangement, which means that switch 9 (.with a time of not less than 120 ms) al3 the short circuit first, and from the reserve device (not shown) for the failure of the switch of the object turn off the switches that are connected to the short-circuit point via switch 15.

After the functioning of the reserve device is an off

15th
switching the switch / ind a repeated switching on of the object is possible

For the reserve relay protection of the circuit 1 to be protected, the above-justified sequence of switching off the achalter 15 and 9 in the event of a short circuit in the circuit 1 to be protected must be set, the switch 15 having to switch off from this protection faster than the switch 9, namely with a lead time of not less than 10 ms «The tuning of the reserve _relay protection ea, which acts with a time delay, is possible with the help of devices of this protection, without having to use special additional technical solutions.

In Fig. 3 is a further embodiment of the device

shown from the AC network to shutdown the electrical system in the event of a short circuit.

The current transformers 19 and 20 of the switches 15 and 9, respectively are equipped with one of the protection relay unit 22 and the intermediate

relay unit 23 existing series chain over the winding of the Power relay 21 connected. One of the outputs of the intermediate relay unit 23 is connected to the control part 28

909881/0823

BATH

nes switch 9 of insufficient breaking capacity in connection, the other output of the same unit is to the control part 25 of the switch 15 with insufficient breaking capacity, connected via the opening contact 24 of the current relay 21 · Between the output of the protective relay unit and the input of the control part 25 of the switch 15 is located a series chain from a closing contact 33 of the current relay 21 and a unit 34 for forcing the response of the Switch 15

The operation of the facility is designed for the company most frequently occurring üall explained in which the switch-off times the container 15 and 9 are equal to each other.

If a short circuit occurs at point 32 and if a short circuit current flows through circuit 1, which is smaller than the breaking capacity of switch 15, current relay 21 does not respond because its response current is less than the maximum permissible breaking current of switch 15 by a reserve factor with insufficient breaking capacity / is assumed \ The protective relay unit 22 and the intermediate relay unit 23 respond, through which an output signal for switching off the switch 15 by means of the control part 25 and the normally closed normally closed contact 24 of the current relay 21 is formed, because the Sfcrom relay 21 is not addressed Has. Here, the two switches are connected · practically from the same 15 and 9, it is desirable to separate off

909881/0823

adjust the switches 15 and 9 so that the switch-off time of switch 15 does not exceed that of switch 9 «The Series chain consisting of the unit 34 and the make contact 33 of the current relay 21 is interrupted with the aid of the contact 33 , since the current relay 21 has not responded

At occurrence of a short circuit and a possible flow of a short-circuit current through the switch with insufficient breaking capacity which exceeds the breaking of this switch, the protective relay unit 22 and the relay 21 to talk to, whereby the contact 24 is opened and the contact 33 is closed · is thereby / a command for switching off) still after the response of the intermediate relay unit 23 /, ie in a time of about 60 · ..80 ms after the appearance of a signal at the output of the protective relay unit 22 generated «The command for switching off the switch 15 arrives after the protective relay unit 22 has been triggered via a chain which consists of the closed contact 33 and the unit 34. The unit 34 ensures that the OFF is issued ( switch-off commands

to switch off

of switch 15> with a time not exceeding 10 ms the triggering of the safety relay unit 22, i.e. faster than the command for switching off switch 9 is given The circuit for the usual passage of the signal used to switch off the switch 15 is blocked by the opening contact 24 after the relay 21 has responded. As a result, the first one of the two i switches becomes the switch 15 switched off.

909881/0823

The switch-off ratios of the latter turn out to be

15th
easy, because the switch switches off practically no short-circuit current for the following reason. The process of leading contact separation of the switch ¹ .15 and the burning of an arc on these contacts leads to the redistribution of the short-circuit current that is supplied by the power supply system 18 via the shunt circuit 2 and the Switches 15 and 9 to the short-circuit point flows A resistance of the arc created between the contacts of switch 15 reduces the short-circuit current flowing through this switch 15 when the circuit is commutated through this container and increases the short-circuit current flowing through switch 9 because the switch 15 and 9 are connected in parallel, which is ensured by the closeness of the shunt circuit 2, the resistance between the contacts of the closed switch 9 being less than that between the contactsa of the switch 15 which is switched off · Finally, at the time of the complete constant contact separation of the

as

Switch 15, the resistance between its contacts is incomparably greater than that of the parallel circuit of switch 9, so practically all of the short-circuit current flows through the latter. The switch 9 is switched off later than the container 15 and commutates the total short-circuit current from the energy supply system 18

It should be noted that all units of the considered Device (units. 22,23,34-, relay 21 etc.) in known?

909881/0323

INSPECTED

Carried out in a manner Here are known switches in question

The invention is for use in AC voltage networks suitable for 110 to 500 kV.

Over time, short-circuit currents within a power supply part have a tendency to increase, so that the individual switches of the Ener ^ ioc.ystomfi

are in conditions in which their breaking capacity does not correspond to the Fegein increasing Short circuit currents. Replacing the switches with more powerful ones is costly and takes time and work for it are considerable. As economically and technically

against it
A possible measure can be the use of switches that are already in operation with insufficient breaking capacity

ride

in the presence of short-circuit currents V, which is made possible by the device according to the invention.

Thus, the economic efficiency and the operational reliability

under permissiveness of the energy supply system use of the

built-in and already in operation switch with

this inadequate breaking capacity increased without being through

replaced a new, more powerful and more expensive switch

must be, whereby it is necessary

"^ V ^ assembly and coordination work can be omitted,

which further the operational reliability

lower

909881/0823

BATH

ta

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Claims (1)

** - * - P 79 418-Ε-61 L / Kdg PATENT CLAIMS f I. Procedure for switching off short-circuit currents in elel • fcrischen High-voltage systems, which are in the circuit of each branch a series chain from a main circuit breaker and an additional circuit breaker, which by similar elek + a'ische Parallel circuits of other branches are bridged, boi the ^m in the presence of a short circuit in one of the circuits dee feeder the main power switch and the auxiliary power scarf tar di '-.-. vs circuit turns off, d ABy in that the auxiliary circuit breaker (15 _t 16 bzw.17) before the off of the main power switch (.9 or 10, 11 or 12, 13 or 14) of the same circuit (1 or 2.3 or 4-, 5 or 6) of the branch is switched off in order to reduce the short-circuit current via the shunt circuits of the branch redistribute and change the short-circuit current direction so that the short-circuit current flows through the main circuit breaker (9 and 10, 11 and 12, 13 and "W-) through which the short-circuited circuit (, 1 or 2,. or 3 ιor 4, or 5 , or 6) of the feeder is switched off. execution
2. Device for the method according to claims 1, the one assigned to each circuit of the feeder Main circuit breaker or additional circuit breaker, a protective relay unit and an intermediate relay unit, the the latter two connected in series with current transformers as well as control units connected to the intermediate relay unit for the main or additional circuit breaker contains, characterized in that 809881/0823 29251Q9 it has a current relay (21), the winding of which is connected between the current transformers (19 and 20) and the protective relay unit (22) and its opening contact (.24,) between the intermediate relay unit (23) and the control part (25) of the additional circuit breaker (15 ) lies. 3 «Device according to claim 2, characterized in that the second input of the control part (25) of the additional circuit breaker (15) to a source {27) for Control 'direct current via a closing contact (26) of the current relay (21) is connected. 4. Device according to claims 2 or 3 »thereby characterized in that the output of the intermediate relay unit (23) with the input of the control part (28; of the main circuit breaker (9) both via the make contact (29) of the current relay (21) and via a chain of a further make contact (30) of the current relay (21) and a delay element (31) is connected. That it comprises a unit for stepping up the response desZusatzleistungsschalters 5 »device according to claim 2, characterized in that (15) on the input side to the output of the protective relay unit (22) and the output side via the ö _c nließkontakt (33) of Stromrelaie (21) is connected to the input of the control unit (25) of the additional power switch (15) 9098Ö1 / 0823