CN100442623C - Protecting method for short-circuit between wire coils of parallel reactor of ultrahigh voltage transmission line - Google Patents

Protecting method for short-circuit between wire coils of parallel reactor of ultrahigh voltage transmission line Download PDF

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CN100442623C
CN100442623C CNB2005100130913A CN200510013091A CN100442623C CN 100442623 C CN100442623 C CN 100442623C CN B2005100130913 A CNB2005100130913 A CN B2005100130913A CN 200510013091 A CN200510013091 A CN 200510013091A CN 100442623 C CN100442623 C CN 100442623C
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negative sequence
phase
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CN1652424A (en
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李永丽
李斌
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Tianjin University
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Abstract

The present invention relates to a protecting method for short circuits between the wire coils of the parallel reactors of an ultrahigh voltage transmission line. A negative sequence voltage and a negative sequence electric current are calculated by a phase voltage and a phase electric current from the leading-out end at high voltage side of a reactor; the short circuits between the wire coils are judged according to the values of the negative sequence voltage and the negative sequence electric current. The judgment course comprises the following steps: judging the direction of negative sequence power when the short circuits between the wire coils have faults by judging the phrase relation between the negative sequence voltage and the negative sequence electric current, and determining whether the faults of the parallel reactors occur inside a district or outside the district. The method not only increases the action sensitivity of protection components when the short circuits between the wire coils occur, but also cancels the characteristic of the impedance compensation of the traditional zero sequence power direction protection. The method provides the fault protection between the wire coils of the parallel reactors, realizes reliable judgment on the district-in or district-out grounding faults of the parallel reactors, and ensures that the parallel reactors can not generate malfunction in the state of non-open phase operation. Through theory analysis and simulation test prove the correctness and efficiency of the new protection principle between the wire coils.

Description

The interturn short circuit protection method of ultra high-tension transmission line shunt reactor
Technical field
The present invention relates to the guard method of power system transmission line shunt reactor, particularly related to a kind of interturn short circuit protection method of the ultra high-tension transmission line shunt reactor based on the negative sequence power orientation principle.
Background technology
The capacitive earth current of remote superhigh pressure, extra-high voltage transmission line is very big, is easy to generate serious overvoltage problem.Use direct-to-ground capacitance, the weakening capacity effect of the inductance energy compensated line of shunt reactor.Simultaneously,, be the success rate of restriction secondary arc current, raising reclosing, often on superhigh pressure and above circuit, all need the shunt reactor of the little reactance of mounting strap neutral point because single-pole reclosing is used widely at supertension line.Therefore shunt reactor obtains to use widely in superhigh pressure, ultra high voltage system as the key equipment of transmission line.
For the superhigh pressure shunt reactor that does not have special switch, its transmission or not operation must be under the electroless state at this circuit to be carried out.Even for the shunt reactor that high-voltage switch gear is arranged, in case it is out of service, power transmission line also can't move.Thus, shunt reactor plays a decisive role to the safe operation of whole system.On-the-spot operation statistics shows that the failure rate of shunt reactor is higher than other equipment of identical electric pressure far away, therefore its protection has been proposed requirements at the higher level.Along with China's electric power system realizes quickening on national network and that build 750kV transmission line process, research large-scale ultrahigh pressure shunt reactor fault and protection thereof are of great importance.
For shunt reactor Inside coil and lead-out wire single-phase earthing or phase fault, differential protecting method can provide sensitive protection.The turn-to-turn short circuit of reactor also is a kind of internal fault form of often seeing.When the short circuit number of turn seldom the time, the three-phase current unbalance that a phase turn-to-turn short circuit causes may be very little, is difficult to detected or finds.And longitudinal differential protection method does not react turn-to-turn fault, and it does not have enough sensitivity when utilizing overcurrent and distance relay to realize the turn-to-turn fault protection, and is subjected to the influence of factors such as magnetizing inrush current big.For improving the sensitivity of inductor turn-to-turn fault, China once developed the reactor interturn short circuit protection of zero sequence power direction principle.But; as a kind of and the most approaching prior art of the present invention, this method is because the zero-sequence component when slight turn-to-turn fault takes place is very little, so zero sequence power direction protection having increased compensation characteristic; but the variation of system operation mode can influence the effect of compensation characteristic, is unfavorable for the use of protecting.
At the deficiency of present shunt reactor protective value, especially the defective of turn-to-turn fault protective value the present invention proposes the inter-turn protection method based on the negative sequence power direction.
Summary of the invention
The objective of the invention is to overcome the defective of prior art; characteristics from turn-to-turn fault preface component; interturn short circuit protection method based on the power transmission line shunt reactor of negative sequence power orientation principle has been proposed; adopt the analysis of negative sequence power directional characteristic, utilize microcomputer to realize analysis and emulation testing fault preface component.
The present invention proposes a kind of interturn short circuit protection method of ultra high-tension transmission line shunt reactor; calculate negative sequence voltage, electric current by phase voltage, the phase current of taking from reactor high-pressure side exit; and carry out the judgement of turn-to-turn short circuit according to this negative sequence voltage, current value, this deterministic process may further comprise the steps:
Carry out fault preface component and calculate,
Computing formula is Wherein,
Figure C20051001309100042
Represent negative sequence voltage,
Figure C20051001309100043
Represent negative-sequence current, U 2rRepresent the real part voltage of negative phase-sequence, I 2rRepresent the real part electric current of negative phase-sequence, U 2iRepresent the imaginary part voltage of negative phase-sequence, I 2iRepresent the imaginary part electric current of negative phase-sequence,
Figure C20051001309100044
Represent a, b voltage between phases,
Figure C20051001309100045
Represent a, b three-phase current,
Figure C20051001309100046
Represent b, c voltage between phases, Represent b, c three-phase current;
Judge the phase relation between negative sequence voltage and the negative-sequence current;
The operating criterion that calculates the negative sequence power direction protection is
Figure C20051001309100048
When negative sequence power telegoniometer formula
Figure C20051001309100049
Satisfy operating criterion, judge that then the shorted-turn fault that is taken place is a troubles inside the sample space; When negative sequence power telegoniometer formula
Figure C200510013091000410
Do not satisfy operating criterion, judge that then the shorted-turn fault that is taken place is an external area error, wherein,
Figure C200510013091000411
Be negative sequence voltage
Figure C200510013091000412
With negative-sequence current
Figure C200510013091000413
Between sensitive angle, get system negative sequence impedance angle.
Compared with prior art; this method since during turn-to-turn fault negative sequence component bigger than the mould value of zero-sequence component; therefore the negative sequence power direction protection has not only improved the sensitivity of turn-to-turn short circuit element action, has also cancelled the impedance-compensated characteristic of traditional zero sequence power direction protection.This method not only provides the protection of shunt reactor turn-to-turn fault; also realize in the shunt reactor district or the reliable judgement of district's external ground fault; this method can guarantee that shunt reactor can misoperation under non-full-operating state simultaneously, correctly reaches validity through what theory analysis and emulation testing had proved new interturn protection principle.
Below in conjunction with embodiment, and be elaborated, so that the present invention is carried out more deep explanation with reference to accompanying drawing.
Description of drawings
Fig. 1 is the equivalent electric circuit that shunt reactor is connected with extra high voltage system;
Fig. 2 is the fault preface net figure of shunt reactor generation turn-to-turn short circuit;
Fig. 3 is the negative sequence network figure of shunt reactor generation turn-to-turn fault;
Negative sequence network figure when Fig. 4 is the inner generation of shunt reactor earth fault;
Negative sequence network figure when Fig. 5 is the outside generation in shunt reactor district earth fault;
Fig. 6 is the performance chart of negative sequence power direction protection;
Negative phase-sequence loop circuit figure when Fig. 7 is open-phase operation.
Embodiment
The Y type that generally adopts shunt reactor inserts the one or both ends of extra high voltage network, and for suppressing problems such as secondary arc current and resonance overvoltage, shunt reactor often has the little reactance of neutral point.The equivalent electric circuit that shunt reactor is connected with extra high voltage system as shown in Figure 1.Z among the figure LBe the shunt reactor impedance; Z NBe the little reactance of neutral point.
During normal the operation, each preface current relationship is I · ka 1 = U · ka 1 Z L , I · ka 2 = I · ka 0 = 0 A . Suppose that turn-to-turn fault takes place shunt reactor A mutually, its impedance variation is Z FBy symmetrical component method, the fault preface net figure that can calculate turn-to-turn short circuit as shown in Figure 2.
By the map analysis of preface net as can be known, during slight turn-to-turn fault, z = Z F - Z L 3 Very little, so forward-order current still is approximately I · ka 1 ≈ U · ka 1 Z L . Forward-order current during as seen slight turn-to-turn fault changes very little, so overcurrent protection does not have enough sensitivity to turn-to-turn fault.Pass between negative phase-sequence and the zero-sequence current is:
I · ka 0 I · ka 2 = Z 2 Σ + Z L Z 0 Σ + Z L + 3 Z N - - - ( 1 )
For extra-high voltage transmission, general Z 0 ∑=(1.5～3) Z 2 ∑sObviously; negative-sequence current mould value during turn-to-turn fault is much larger than zero-sequence current; but the preface electric current when considering slight turn-to-turn fault is less; utilize fault preface current weight can not constitute the performance excellent protection merely, therefore the present invention proposes new interturn protection principle based on the negative sequence power direction to turn-to-turn fault.
Utilize the protective relaying device of microcomputer to be easy to realize the calculating of fault preface component, can realize the turn-to-turn fault guard method that utilizes the power transmission line shunt reactor that the negative sequence power orientation principle realizes proposed by the invention.Its concrete steps comprise: by judging the phase relation between negative sequence voltage and the negative-sequence current, the direction of clear and definite negative sequence power determines whether to take place shorted-turn fault, or earth fault occurs in outside the interior still district, district.Define the negative sequence voltage of negative sequence power direction protection for this reason
Figure C20051001309100061
Take from the negative sequence voltage on the reactor exit circuit; Negative-sequence current
Figure C20051001309100062
Take from the high-pressure side of reactor, positive direction is that line flows is to reactor.
Below by specific embodiment, further specify technical scheme of the present invention:
1. utilize the specific implementation method that the negative sequence power directional characteristic carries out in the shunt reactor district, external area error is judged
By symmetrical component method as can be known, when unbalanced fault takes place, can insert one group of asymmetric potential source in network in the fault point, each phase electromotive force of potential source with above-mentioned each asymmetrical voltage equal and opposite in direction, direction are opposite mutually.In negative phase-sequence loop during single-phase turn-to-turn short circuit vertical negative phase-sequence false voltage must be arranged , establish X L1, X L2Be respectively the reactance of both sides, fault point, X NBe the little reactance of neutral point; X S2Be the system equivalent negative sequence reactance, then the negative sequence network of turn-to-turn fault as shown in Figure 3.When turn-to-turn fault takes place, take from the on high-tension side negative sequence voltage of reactor With negative-sequence current
Figure C20051001309100065
Between the pass be:
U · 2 = - I · 2 · j X S 2 - - - ( 2 )
The shunt reactor of general superhigh pressure, UHV transmission line is single-phase oil immersion type, so generally only consider single phase ground fault.Be located at reactor inside and earth fault occurs, horizontal negative sequence voltage appears in the fault point
Figure C20051001309100067
Its negative sequence network as shown in Figure 4, i.e. negative phase-sequence loop during the reactor internal ground fault.
As seen the negative sequence voltage during the reactor internal ground fault
Figure C20051001309100068
With negative-sequence current
Figure C20051001309100069
Between the pass be:
U · 2 = - I · 2 · j X S 2 - - - ( 3 )
When system side generation earth fault, the negative sequence network when promptly earth fault occurs in outside the shunt reactor district as shown in Figure 5, i.e. negative phase-sequence loop during the external ground fault.
Negative sequence voltage during reactor external ground fault
Figure C200510013091000611
With negative-sequence current
Figure C200510013091000612
Between the pass be:
U · 2 = I · 2 · j X L - - - ( 4 )
In the following formula, X LRepresent the induction reactance of shunt reactor.
By above analysis as can be known, fault occurs in the district or the district is outer can be judged by position, negative phase-sequence source in system's negative sequence network, thus the sensitivity of protection action when having improved turn-to-turn fault greatly.
Therefore the operating criterion of the negative sequence power direction protection of the present invention's proposition is as follows:
Figure C20051001309100071
In the formula
Figure C20051001309100072
System negative sequence impedance angle is depended at maximum sensitive angle.For guaranteeing negative sequence power direction protection reflected reactance device turn-to-turn fault and internal ground fault, be that net resistance is considered with the negative sequence impedance, then
Figure C20051001309100073
Therefore, the operating characteristics of negative sequence power direction protection as shown in Figure 6.
2. the action characteristic analysis of negative sequence power direction protection during non full phases operation of line
Be the stable operation of assurance system and the reliability of power supply, single-pole reclosing is widely used on supertension line.After tripping because of breaking down on the arbitrary phase place of supertension line, circuit enters non-full-operating state.Because three-phase voltage is asymmetric, therefore can produce negative sequence voltage, negative-sequence current, the negative phase-sequence loop of system's this moment when open-phase operation is as shown in Figure 7.
This shows that under the open-phase operation situation, the negative sequence voltage of reactor exit is taken from bus or taken from circuit essential distinction.When
Figure C20051001309100074
Pass when taking from bus bar side and line side between negative sequence voltage and the negative-sequence current is:
U · 2 M = - j I · 2 X S 2 U · 2 L = j I · 2 X L - - - ( 6 )
By (6) formula as seen, take from bus bar side (negative sequence voltage when negative sequence voltage
Figure C20051001309100076
), malfunction must take place in the negative sequence power direction protection; Take from line side (negative sequence voltage and work as negative sequence voltage
Figure C20051001309100077
), negative sequence voltage Be ahead of negative-sequence current
Figure C20051001309100079
So the negative sequence power direction protection can malfunction.
For the various situations of full operation mutually or fault, the result of determination that negative sequence voltage is taken from line side or bus bar side is consistent.Therefore, the negative sequence voltage of negative sequence power direction protection should be taken from the line side of shunt reactor exit, and negative-sequence current is taken from the reactor high-pressure side, and the definition positive direction is to reactor by line flows.By last analysis as can be known, the negative sequence power direction protection not only can effectively be judged the inside and outside earth fault in district, avoids simultaneously malfunction takes place under the non-full-operating state, also provides sensitive protective feature for inductor turn-to-turn fault.
3. in microcomputer, utilize the negative sequence power directional characteristic to carry out the specific implementation method of reactor fault judgement
The microcomputer relaying protection is easy to realize the calculating to fault preface component.Can calculate negative sequence voltage, electric current by the phase voltage of taking from reactor high-pressure side exit, phase current:
Figure C20051001309100081
By Microcomputer Protection realize negative sequence power direction protection characteristic that (5) formula expresses as shown in the formula:
Figure C20051001309100082
When (8) when formula satisfies, then shorted-turn fault has taken place or earth fault in the district has been arranged in explanation.
As seen, negative sequence power direction protection principle is clear, is easy to realize, and turn-to-turn fault is had very high sensitivity, therefore can be used as the main protection of shunt reactor turn-to-turn fault.
Define the negative sequence voltage of negative sequence power direction protection for this reason
Figure C20051001309100083
Take from the negative sequence voltage on the reactor exit circuit; Negative-sequence current
Figure C20051001309100084
Take from the high-pressure side of reactor, positive direction is that line flows is to reactor.

Claims (3)

1. the interturn short circuit protection method of a ultra high-tension transmission line shunt reactor; calculate negative sequence voltage, electric current by phase voltage, the phase current of taking from reactor high-pressure side exit; and carry out the judgement of turn-to-turn short circuit according to this negative sequence voltage, current value, this deterministic process may further comprise the steps:
Carry out fault preface component and calculate,
Computing formula is
Figure C2005100130910002C1
Wherein, Represent negative sequence voltage,
Figure C2005100130910002C3
Represent negative-sequence current, U 2rRepresent the real part voltage of negative phase-sequence, I 2rRepresent the real part electric current of negative phase-sequence, U 2iRepresent the imaginary part voltage of negative phase-sequence, I 2iRepresent the imaginary part electric current of negative phase-sequence,
Figure C2005100130910002C4
Represent a, b voltage between phases,
Figure C2005100130910002C5
Represent a, b three-phase current,
Figure C2005100130910002C6
Represent b, c voltage between phases,
Figure C2005100130910002C7
Represent b, c three-phase current;
Judge the phase relation between negative sequence voltage and the negative-sequence current;
The operating criterion that calculates the negative sequence power direction protection is
Figure C2005100130910002C8
When negative sequence power telegoniometer formula
Figure C2005100130910002C9
Satisfy operating criterion, judge that then the shorted-turn fault that is taken place is a troubles inside the sample space; When negative sequence power telegoniometer formula
Figure C2005100130910002C10
Do not satisfy operating criterion, judge that then the shorted-turn fault that is taken place is an external area error, wherein,
Figure C2005100130910002C11
Be negative sequence voltage
Figure C2005100130910002C12
With negative-sequence current
Figure C2005100130910002C13
Between sensitive angle, get system negative sequence impedance angle.
2. the interturn short circuit protection method of ultra high-tension transmission line shunt reactor as claimed in claim 1 is characterized in that, when transmission line enters non-full-operating state, and its negative sequence voltage
Figure C2005100130910002C14
Should take from the line side, at this moment negative sequence voltage
Figure C2005100130910002C15
With negative-sequence current
Figure C2005100130910002C16
Between the pass be U · 2 = j I · 2 X L , X LInduction reactance for shunt reactor.
3. the interturn short circuit protection method of ultra high-tension transmission line shunt reactor as claimed in claim 1 is characterized in that, described fault preface component is realized by the microcomputer relaying protection.
CNB2005100130913A 2005-01-13 2005-01-13 Protecting method for short-circuit between wire coils of parallel reactor of ultrahigh voltage transmission line Expired - Fee Related CN100442623C (en)

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CN104330705B (en) * 2014-11-14 2017-07-28 国家电网公司 Circuit inter-phase fault single-end ranging based on phase-to phase fault location factor
CN105006802B (en) * 2015-07-15 2017-10-31 南京国电南自电网自动化有限公司 Reactor protection method based on electric current than width formula order components
CN105203903B (en) * 2015-09-14 2018-11-06 国网福建省电力有限公司 Based on dynamic data window electric transmission line phase fault discriminating direction method
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CN106786368B (en) * 2016-12-26 2018-12-18 云南电网有限责任公司电力科学研究院 The guard method of dry type hollow shunt reactor based on voltage-phase variable quantity
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