Summary of the invention
Problem to be solved by this invention is; it is various electric pressure electric substation protection equipment for transformer that a kind of transmission and distribution networks that can be applied to is provided, and operating principle is simple, reliability is high, excise fast the relay protecting method of the various electric pressure dead-zone faults of each side of transformer.
Provide the technical scheme of the inventive method below.
At the do protective device of two-winding transformer, three-winding transformer, autotransformer or other transformers of various electric pressures of the power transformation of the applied transmission and distribution networks of method of the present invention, in theory, transformer has several working voltage grades to pass through breaker interval equipment (by isolating switch, circuit breaker, the equipment such as current transformer form) be connected with external circuit equipment, as long as a certain side circuit breaker of transformer both sides only has this side of transformer to have current transformer (being called for short TA), and bus bar side does not have TA, just there is several failure in transformer dead zone position (if all there is TA circuit breaker both sides, this circuit breaker loop does not just have dead-zone fault position), there are 2 working voltage grades to be connected with external circuit equipment by breaker interval equipment, just have 2 failure in transformer dead zone positions at least, there are 3 working voltage grades to be connected with external circuit equipment by breaker interval equipment, just have 3 failure in transformer dead zone positions (if 1 working voltage grade has 2 breaker interval equipment, this working voltage grade side is 2 failure in transformer dead zone positions) at least.
For sake of convenience, breaker interval equipment generation failure in transformer dead zone with one of them working voltage grade of transformer, describe quick startup and excise the method for this fault, the transformer of other electric pressure and transformer are two-winding transformer, three-winding transformer, autotransformer or other transformers, or each side of transformer is by the combination of other electric pressure, its method is similar, no longer tired stating.This breaker interval equipment is comprised of equipment such as isolating switch, circuit breaker, TA; TA has respectively several groups of secondary winding, and these several groups of secondary winding access respectively the secondary devices such as transformer differential protection (backup protection), bus differential protecting, measuring from bus bar side to transformer side.Bushing shell for transformer place has also installed sleeve pipe TA.The TA that each side backup protection of 110kV and following transformer is used separates with transformer differential protection, the TA of use be different TA(such as differential protection is used the TA of circuit breaker place, and sleeve pipe TA is used in backup protection), or the different secondary winding of TA.Its control method comprises following control procedure:
In the tripping operation of transformer side dead-zone fault is controlled, set following condition:
Condition one, exit relay is tripped in operate condition for trip protection exit relay in operate condition or other electric parameters protection (such as this side bus differential protection) in this rear flank of transformer;
Condition two, when condition one meets, starts pulsatile once T time open protection (i.e. open and protection T time; The desirable 2t1 of T, 300ms, lower same);
Condition three, this side of transformer A phase or B phase or C phase current Ipmax reach startup value, or zero-sequence current Io or negative-sequence current I
2reach startup value,>=setting value;
When above-mentioned condition meets, through time delay t1(as 150ms) this side transformer differential of backed off after random transformer protection TA, this side electric current of transformer does not participate in transformer differential protection Current calculation; When above-mentioned arbitrary condition does not meet or after the arrival of open and protection time T, this side transformer differential of 0s access transformer TA, this side electric current of transformer participates in transformer differential protection Current calculation.
Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; be equivalent to the comprehensive poor stream of transformer differential protection from being 0 or the very little short circuit current that becomes short dot originally; just make transformer differential protection that this fault is judged as to troubles inside the sample space by external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of tripping transformer, have excised this fault.
Judgement transformer this side A phase or B phase or C also have electric current mutually, can gather this side differential protection of transformer TA electric current, and this current ration can be adjusted by escaping this side maximum load current of transformer; When this side of transformer is effectively earthed system, zero-sequence current or negative-sequence current definite value can have enough sensitivity adjust (sensitivity coefficient desirable >=3) by this side bus earth fault of transformer.
When a certain side electric pressure of transformer is 35kV and following system, this system is generally isolated neutral system or compensated distribution network, and this side zero-sequence current criterion of transformer can.If resistance grounded system, this side zero-sequence current criterion of transformer can be used.
The present invention compares with the method for existing excision failure in transformer dead zone, and tool has the following advantages:
1. the do technical scheme of the two-winding transformer of various electric pressures, three-winding transformer, the isallobaric device protective device of autotransformer of the power transformation that is applicable to transmission and distribution networks.
2. after the method judgement dead-zone fault, adopt time delay backed off after random transformer fault side transformer differential TA, transformer fault side electric current does not participate in the method for transformer differential protection Current calculation, and criterion is simple and practical; After judgement dead-zone fault, compared with just quick starting transformer differential protection after short time delay, reached the object of quick this dead-zone fault of excision;
3. owing to not adding breaker open operation position contact in criterion; for electric substation's side bus fault; bus protection action or transformer fault side backup protection action; but transformer fault side circuit breaker miss operation (breaker failure); the present invention program also can be after judgement circuit breaker tripping time delay t1(150ms) backed off after random transformer fault side transformer differential TA; starting transformer differential protection, excises this fault fast.
4. increase the T time loop of short time open and protection, strengthened the fail safe of this failure in transformer dead zone protection.
Embodiment
The 220kV autotransformer protection of 220kV electric substation of take is example; the method that failure in transformer dead zone starts this fault of excision is fast described; the transformer of other electric pressure and transformer are two-winding transformer, three-winding transformer, autotransformer or other transformers; or each side of transformer is by the combination of other electric pressure; its method is similar, no longer tired stating.Main wiring diagram of ,Wei 220kV electric substation part as shown in Figure 2, a 220kV autotransformer, transformer is equiped with high-pressure side circuit breaker 1QF, medium voltage side circuit breaker 2QF, low-pressure side circuit breaker 3QF; Circuit breaker 1QF place, high-pressure side, medium voltage side circuit breaker 2QF place, low-pressure side circuit breaker 3QF place are equiped with respectively one group of independently TA, and TA has respectively several groups of secondary winding, and high voltage side of transformer, medium voltage side and neutral point place have also installed sleeve pipe TA.Each side of 220kV transformer TA configuration as shown in Figure 2, wherein high voltage side of transformer (220kV) the circuit breaker TA of place secondary winding is connected to respectively first set transformer longitudinal differential and backup protection by bus bar side to transformer side, (220kV tranformer protection generally adopts main protection and backup protection unified collocation for the second cover transformer longitudinal differential and backup protection, be the public same group of TA secondary winding of each side of main protection and backup protection, secondary windings of PT, and main protection and backup protection all hardware equipment and software are in same cabinet), first set 220kV bus differential protecting, the second cover 220kV bus differential protecting (is pressed Q/GDW_175 < < transformer, the tranformer protection of high-voltage shunt reactor and bus protection and servicing unit standardized designs standard > > design does not arrange special breaker failure current circuit, by bus differential protecting, realized, otherwise have, special breaker failure current circuit is set), metering, measure, transformer medium voltage side (110kV) the circuit breaker TA of place secondary winding is connected to respectively first set transformer longitudinal differential and backup protection, the second cover transformer longitudinal differential and backup protection, 110kV bus differential protecting, metering, measurement by bus bar side to transformer side, step down side (35kV or the 10kV etc.) TA of circuit breaker place secondary winding is connected to respectively first set transformer longitudinal differential and backup protection, the second cover transformer longitudinal differential and backup protection (bus protection), failure wave-recording, metering, measurement etc. by bus bar side to transformer side.
Provide the inventive method below and be applied to the embodiment that failure in transformer dead zone excises this fault fast:
1, the quick cutting method of high voltage side of transformer dead-zone fault
(1) as the TA at the circuit breaker place, TA(Ji high-pressure side, high-pressure side that high voltage side of transformer circuit breaker lQF and transformer differential protection are used) between while there is phase fault or earth fault; fault is outside transformer longitudinal linked differential protection scope; but within first set 220kV bus differential protecting, the second cover 220kV bus differential protecting protection range, first set 220kV bus differential protecting, the second cover 220kV bus differential protecting start all switches of this fault bus of tripping (containing high voltage side of transformer circuit breaker lQF).If other side of transformer has power supply, although circuit breaker 1QF tripping, but fault is excision not, fault phase still has certain phase current or zero-sequence current or negative-sequence current to surpass setting value, therefore first set 220kV bus differential protecting, the second cover 220kV bus differential protecting still moves and does not return to (or high voltage side of transformer backup protection startup delay time still moves and do not return to backup protection), start open and protection 300ms loop, therefore three conditions of judgement dead-zone fault meet, after time delay t1 is 150ms, exit transformer high-voltage side transformer differential TA, be that high voltage side of transformer electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; be equivalent to the comprehensive spill current of transformer differential protection from being 0 or the very little short circuit current that becomes short dot originally; just make transformer differential protection judge that this dead-zone fault becomes troubles inside the sample space from external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(2) when high voltage side of transformer circuit breaker lQF at open position, above-mentioned high voltage side of transformer dead-zone fault occurs; fault is outside transformer longitudinal linked differential protection scope; but within first set 220kV bus differential protecting, the second cover 220kV bus differential protecting protection range, first set 220kV bus differential protecting, the second cover 220kV bus differential protecting start all switches of this fault bus of tripping.If other side of transformer has power supply; although circuit breaker 1QF is at open position; but fault phase has short circuit current or zero-sequence current or negative-sequence current to surpass setting value; first set 220kV bus differential protecting, the second cover 220kV bus differential protecting action or high voltage side of transformer backup protection start delay time to action; start open and protection 300ms loop; therefore three conditions of judgement dead-zone fault meet; after time delay t1 is 150ms; exit transformer high-voltage side transformer differential TA, high voltage side of transformer electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; be equivalent to the comprehensive spill current of transformer differential protection from being 0 or the very little short circuit current that becomes short dot originally; just make transformer differential protection judge that this dead-zone fault becomes troubles inside the sample space from external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(3) if 220kV busbar fault, although two cover 220kV bus differential protecting actions, two cover 220kV bus differential protectings start other all switches of this fault bus of tripping, but high voltage side of transformer circuit breaker lQF miss operation, if other side of transformer has power supply, not excision of fault, fault phase still has electric current or zero-sequence current or negative-sequence current to surpass setting value, therefore first set 220kV bus differential protecting, the second cover 220kV bus differential protecting still moves and does not return to (or high voltage side of transformer backup protection startup delay time still moves and do not return to backup protection), start open and protection 300ms loop, therefore three conditions of judgement dead-zone fault meet, after time delay t1 is 150ms, exit transformer high-voltage side transformer differential TA, be that high voltage side of transformer electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; be equivalent to the comprehensive spill current of transformer differential protection from being 0 or the very little short circuit current that becomes short dot originally; just make transformer differential protection judge that this dead-zone fault becomes troubles inside the sample space from external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(4) if this other side of electric substation's transformer does not have power supply, transformer fault side does not have fault current to flow through, therefore three conditions of judgement dead-zone fault do not meet, just can not start and exit transformer high-voltage side transformer differential TA.If 220kV bus differential protecting or high voltage side of transformer backup protection one direct acting do not return, locking transformer dead zone protection after 300ms, concurrent alarm signal.
2, the quick cutting method of transformer medium voltage side dead-zone fault
(1) when the medium voltage side TA(that transformer medium voltage side circuit breaker 2QF and transformer differential protection are used is the TA at medium voltage side circuit breaker place) between while there is phase fault or earth fault, fault is outside transformer longitudinal linked differential protection scope, but within the protection range of 110kV bus differential protecting, 110kV bus differential protecting starts all switches of this fault bus of tripping (containing transformer medium voltage side circuit breaker 2QF), although circuit breaker 2QF tripping, but fault is excision not, fault phase still has electric current or zero-sequence current or negative-sequence current to surpass setting value, therefore 110kV bus differential protecting still moves and does not return to (or transformer medium voltage side backup protection startup delay time still moves and do not return to backup protection), start open and protection 300ms loop, therefore three conditions of judgement dead-zone fault meet, after time delay t1 is 150ms, exit transformer medium voltage side transformer differential TA, be that transformer medium voltage side electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; be equivalent to the comprehensive spill current of transformer differential protection from being 0 or the very little short circuit current that becomes short dot originally; just make transformer differential protection judge that this dead-zone fault becomes troubles inside the sample space from external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(2) when transformer medium voltage side circuit breaker 2QF at open position, above-mentioned transformer medium voltage side dead-zone fault occurs; fault is outside transformer longitudinal linked differential protection scope; but within 110kV bus differential protecting protection range, 110kV bus differential protecting starts all switches of this fault bus of tripping.Although circuit breaker 2QF is at open position; but fault phase has short circuit current or zero-sequence current or negative-sequence current to surpass setting value; the action of 110kV bus differential protecting or the backup protection of transformer medium voltage side start delay time to action; start open and protection 300ms loop; therefore three conditions of judgement dead-zone fault meet; after time delay t1 is 150ms, exit transformer medium voltage side transformer differential TA, transformer medium voltage side electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; be equivalent to the comprehensive spill current of transformer differential protection from being 0 or the very little short circuit current that becomes short dot originally; just make transformer differential protection judge that this dead-zone fault becomes troubles inside the sample space from external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(3) if 110kV busbar fault, although 110kV bus differential protecting action, 110kV bus differential protecting starts other all switches of this fault bus of tripping, but transformer medium voltage side circuit breaker 2QF tripping, but fault is excision not, fault phase still has electric current or zero-sequence current or negative-sequence current to surpass setting value, therefore 110kV bus differential protecting still moves and does not return to (or transformer medium voltage side backup protection startup delay time still moves and do not return to backup protection), start open and protection 300ms loop, therefore three conditions of judgement dead-zone fault meet, after time delay t1 is 150ms, be that transformer medium voltage side electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; be equivalent to the comprehensive spill current of transformer differential protection from being 0 or the very little short circuit current that becomes short dot originally; just make transformer differential protection judge that this dead-zone fault becomes troubles inside the sample space from external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(4) if 110kV bus differential protecting or high voltage side of transformer backup protection one direct acting do not return, locking transformer dead zone protection after 300ms, concurrent alarm signal.
3, the quick cutting method of step down side dead-zone fault
(1) step down side electric pressure is generally 35kV and following system; this system is generally isolated neutral system or compensated distribution network or grounded system via resistance; generally do not install special bus differential protecting, by a set of step down side backup protection wherein, as bus, protected.When low-pressure side TA(that step down side circuit breaker 3QF and transformer differential protection are used is the TA at low-pressure side circuit breaker place) between while there is phase fault or earth fault (during grounded system via resistance); fault is outside transformer longitudinal linked differential protection scope; but within the protection range of step down side backup protection, step down side backup protection starts tripping step down side circuit breaker 3QF.Although circuit breaker 3QF tripping, but fault is excision not, fault phase still has electric current or negative-sequence current or zero-sequence current to surpass setting value (during grounded system via resistance), therefore low-voltage bus bar differential protection still moves and does not return to that (or step down side backup protection is not (when there is no bus protection, by a set of low-pressure side backup protection wherein as bus protection) start delay time and still move and do not return to backup protection), start open and protection 300ms loop, therefore three conditions of judgement dead-zone fault meet, after time delay t1 is 150ms, exit transformer low voltage side transformer differential TA, be that step down side electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; just make this dead-zone fault become troubles inside the sample space from transformer differential protection external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(2) when step down side circuit breaker 3QF is when above-mentioned low-pressure side dead-zone fault occurs open position, fault is outside transformer longitudinal linked differential protection scope, but within the protection range of step down side backup protection, step down side backup protection starts; Although circuit breaker 3QF is at open position; but fault phase still has electric current or negative-sequence current or zero-sequence current to surpass setting value (during grounded system via resistance); when the backup protection of step down side backup protection low-pressure side starts delay time action; start open and protection 300ms loop; therefore three conditions of judgement dead-zone fault meet; after time delay t1 is 150ms, exit transformer low voltage side transformer differential TA, step down side electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; just make this dead-zone fault become troubles inside the sample space from transformer differential protection external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(3) if low-voltage bus bar fault; although step down side backup protection action; but step down side circuit breaker 2QF tripping; so fault is excision not; fault phase still has electric current or negative-sequence current to surpass setting value; step down side backup protection starts delay time and still moves and do not return to backup protection; start open and protection 300ms loop; therefore three conditions of judgement dead-zone fault meet; after time delay t1 is 150ms; exit transformer low voltage side transformer differential TA, step down side electric current does not participate in transformer differential protection Current calculation.Because transformer differential protection exits fault side electric current from transformer differential protection Current calculation; just make this dead-zone fault become troubles inside the sample space from transformer differential protection external area error; transformer differential protection is with regard to the trip(ping) circuit of action launching transformer general export; other circuit breakers of saltus step depressor, have excised this fault.
(4) if step down side backup protection one direct acting does not return, locking transformer dead zone protection after 300ms, concurrent alarm signal.
4, the quick cutting method of other failure in transformer dead zone
When a certain side electric pressure of transformer is 35kV and following system, this system is generally isolated neutral system or compensated distribution network or grounded system via resistance, and the quick cutting method of this side dead-zone fault of transformer can be with reference to the quick cutting method of 220kV step down side dead-zone fault.
When a certain side electric pressure of transformer is 110kV or 220kV and above system, this system is generally effectively earthed system, and the quick cutting method of this side dead-zone fault of transformer can be with reference to 220kV high voltage side of transformer or the quick cutting method of medium voltage side dead-zone fault.
When transformer is two-winding transformer, be equivalent to above-mentioned three-winding transformer and lacked a side, only need to consider that dead-zone fault quick cutting method in transformer both sides is just passable.