CN106908697B - A kind of distribution network fault line selection method of synthetic power-frequency and transient reactive power direction - Google Patents
A kind of distribution network fault line selection method of synthetic power-frequency and transient reactive power direction Download PDFInfo
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Abstract
The present invention relates to distribution network failure detection technique fields, and in particular to a kind of distribution network fault line selection method of synthetic power-frequency and transient reactive power direction.After singlephase earth fault occurs, the present invention chooses the biggish outlet of transient zero-sequence current Amplitude Ration as the alternative outlet of failure first, then the transient reactive power and power frequency reactive power of the alternative outlet of failure are calculated, its transient reactive power is modified using the sign function of power frequency reactive power, recycle revised transient reactive power finds out failure outlet；The present invention solves the problems, such as the uncertain single-phase earth fault line selection of TV, TA polarity in small current neutral grounding mode distribution system.TV, TA polarity of power distribution network are unknown in practical application, solve the problems, such as the uncertain single-phase grounding fault line selection in small current grounding of TV, TA polarity, there is extensive practical application value.
Description
Technical field
The present invention relates to distribution network failure detection technique fields, and in particular to a kind of synthetic power-frequency and transient reactive power side
To distribution network fault line selection method.
Background technique
China's 6~35kV medium voltage distribution network mostly uses resonance neutral grounding, and arc suppression coil is typically in overcompensation state.
Although improving in this way, fault self-recovery is horizontal and power supply reliability, the inductive current of overcompensation keep faulty line power frequency zero sequence electric
Stream polarity is identical as sound circuit, amplitude is even less than sound circuit, so that tradition utilizes the failure line selection side of stable state electrical quantity
Method there is failure amounts it is not prominent, unstable or even uncertain the problems such as, not can guarantee the reliability and sensitivity of route selection.Due to
Ground fault transient current amplitude is usually the several times of power current to decades of times, up to hundreds of amperes, and not by arc suppression coil
Compensation way influences, therefore transient line selection reliability in resonator system is higher.By development in recent years, transient state electricity is utilized
The low-current ground fault line selection technology of tolerance has realized breakthrough.
It is a kind of typical case side of transient state route selection using fault transient reactive power direction (hereinafter referred to as transient power) route selection
Method.Transient power selection method is the transient reactive power direction by comparing each outlet, and direction is different with other outlets to be
Failure outlet is busbar grounding failure if all outlet transient reactive powers direction is all identical.The method does not require nothing more than
Zero sequence current mutual inductor (TA) polarity between each outlet is consistent, the pole TA for also requiring zero sequential potential transformer (TV) corresponding
Property be consistent, just can guarantee the correctness in transient power direction, and then carry out correct route selection.But very due to conventional electrical distribution route
Direction protection is used less, and the installation of live TV and TA are seldom in view of the polar relationship between mutual inductor, it is easy to due to primary
Side secondary side wiring is not corresponding to cause error-polarity connection, keeps transient power direction calculating uncertain and causes route selection mistake.
Number of patent application: CN201210479994.0, a kind of title: resonant earthed system choosing based on reactive power flow direction
Line method proposes logical respectively with paper " the resonant earthed system low-current ground fault line selection of comprehensive transient state and power frequency information "
The method for crossing the consistency of each outlet transient reactive power and power frequency reactive power flow direction after comparing small current grounding fault carries out
Route selection, this method eliminates the uncertain influences of TV, TA polarity, improve the reliability and adaptability of transient state route selection.But it should
Algorithm is not readily understood in principle, route selection process slightly complicated.
Summary of the invention
In order to which failure line selection when solving to occur in the uncertain small current neutral grounding system of TV, TA polarity single-phase earthing is asked
Topic, the present invention provides the distribution network fault line selection method of a kind of synthetic power-frequency and transient reactive power direction, particular technique sides
Case is as follows:
A kind of synthetic power-frequency and the distribution network fault line selection method in transient reactive power direction the following steps are included:
(1) zero-sequence current and bus residual voltage in each outlet bus exit of on-line acquisition system, when monitoring bus
When residual voltage amplitude is more than pre-set bus residual voltage amplitude thresholds, illustrate that singlephase earth fault has occurred in system；
(2) the biggish n outlet of transient zero-sequence current Amplitude Ration is chosen as the alternative outlet of failure；Wherein n > 1；
(3) transient reactive power for the alternative outlet of n failure chosen in step (2) is calculated according to following formula:
；
Wherein, number of the k for the alternative outlet of failure, k=1,2, n；TFor the transient process duration,
For the transient zero-sequence current in the bus exit of the alternative outlet k of failure,For bus transient zero-sequence voltage；If,
Then indicate that the transient reactive power of the alternative outlet k of failure flows to the alternative outlet k of failure by bus, the alternative outlet k of failure is sound
Route；If, then it represents that the transient reactive power of the alternative outlet k of failure flows to bus, failure by the alternative outlet k of failure
Alternative outlet k is faulty line；If the faulty alternative outlet of institute is all satisfied, then system is busbar grounding failure；
(4) according to following formulaCalculate step (2) in choose faulty alternative outlet power frequency reactive power:
；
Wherein, number of the k for the alternative outlet of failure, k=1,2, n；For the zero sequence of the alternative outlet k of failure
Electric current power frequency component,For bus residual voltage power frequency component,TFor the transient process duration；If, then
Indicate that power frequency reactive power flows to the alternative outlet k of failure by bus；If, then it represents that power frequency reactive power is standby by failure
It selects line k and flows to bus；
(5) transient reactive power of the alternative outlet of failure is repaired using the power frequency reactive power of the alternative outlet of failure
Just, then more revised transient reactive power carries out route selection according to the direction of revised transient reactive power, if amendment
Transient reactive power afterwards is, then
；
If, then it represents that transient reactive power flows to the alternative outlet k of failure by bus, and the alternative outlet k of failure is
Sound circuit；If, then it represents that transient reactive power flows to bus, the alternative outlet k of failure by the alternative outlet k of failure
For faulty line；If all routes are all satisfied, then system is busbar grounding failure.
Further, it is a power frequency period that T is chosen in the step (4).
The invention has the benefit that
The present invention provides the distribution network fault line selection method of a kind of synthetic power-frequency and transient reactive power direction, the present invention
Independent of TV, TA polarity, power frequency reactive power when passing through singlephase earth fault is modified transient reactive power, in turn
Route selection is carried out using revised transient reactive power；The invention comprehensively utilizes the transient reactive power of outlet and power frequency are idle
Power eliminates the influence of TV, TA error-polarity connection, and algorithm is simple, should be readily appreciated that and route selection reliability is high.Distribution in practical application
TV, TA polarity of net are unknown, and the present invention solves to be sent out in the small current neutral grounding system in the probabilistic power distribution network of TV, TA polarity
Failure line selection problem when raw single-phase earthing, there is extensive practical application value.
Detailed description of the invention
Attached drawing 1 is the process of the distribution network fault line selection method in a kind of synthetic power-frequency of the present invention and transient reactive power direction
Figure；
Attached drawing 2 is that each outlet residual voltage and zero-sequence current waveform when intermittent grounding fault occur for small current neutral grounding system
Figure.
Specific embodiment
In order to better understand the present invention, the present invention will be further explained below with reference to the attached drawings and specific examples:
As shown in Figure 1, a kind of synthetic power-frequency and the distribution network fault line selection method in transient reactive power direction include following
Step:
(1) zero-sequence current and bus residual voltage in each outlet bus exit of on-line acquisition system, when monitoring bus
When residual voltage amplitude is more than pre-set bus residual voltage amplitude thresholds, illustrate that singlephase earth fault has occurred in system；
If bus residual voltage amplitude is U0, bus residual voltage amplitude thresholds are U0set, work as U0>U0set, it is single-phase to illustrate that system has occurred
Ground fault；Then carry out step (2)；If bus residual voltage amplitude is not above the bus residual voltage amplitude thresholds of setting
U0setWhen, i.e.,, illustrating system, there is no singlephase earth faults, then continue to each outlet bus exit of system
Zero-sequence current and bus residual voltage are acquired and monitor；
(2) the biggish n outlet of transient zero-sequence current Amplitude Ration is chosen as the alternative outlet of failure；Wherein n > 1；
(3) according to following formulaCalculate the transient reactive power for the alternative outlet of n failure chosen in step (2):
；
Wherein, number of the k for the alternative outlet of failure, k=1,2, n；TFor the transient process duration,
For the transient zero-sequence current in the bus exit of the alternative outlet k of failure,For bus transient zero-sequence voltage；If,
Then indicate that the transient reactive power of the alternative outlet k of failure flows to the alternative outlet k of failure by bus, the alternative outlet k of failure is sound
Route；If, then it represents that the transient reactive power of the alternative outlet k of failure flows to bus, failure by the alternative outlet k of failure
Alternative outlet k is faulty line；If the faulty alternative outlet of institute is all satisfied, then system is busbar grounding failure；
(4) according to following formulaCalculate step (2) in choose faulty alternative outlet power frequency reactive power:
；
Wherein, number of the k for the alternative outlet of failure, k=1,2, n；For the zero sequence of the alternative outlet k of failure
Electric current power frequency component,For bus residual voltage power frequency component,TFor the transient process duration, it is chosen for a power frequency
Period, i.e. 20mS, if, then it represents that power frequency reactive power flows to the alternative outlet k of failure by bus；If,
Then indicate that power frequency reactive power flows to bus by the alternative outlet k of failure；
(5) transient reactive power of the alternative outlet of failure is repaired using the power frequency reactive power of the alternative outlet of failure
Just, then more revised transient reactive power carries out route selection according to the direction of revised transient reactive power；In resonance
In earthed system, since arc suppression coil is typically in overcompensation state, faulty line is the perceptual power frequency that bus is flowed to by route
It is identical by bus to flow to the capacitive power frequency reactive power of route with sound circuit for reactive power.That is power frequency power direction and TA
Whether be reversely connected it is related, and with whether faulty line is unrelated.When outlet TA polarity is without reversal connection, the power frequency reactive power of all outlets
It is positive；When certain outlet TA error-polarity connection, the transient reactive power and power frequency reactive power of the outlet change simultaneously symbol (simultaneously
Multiplied by -1), power frequency reactive power must be negative.Therefore, no matter whether TA polarity is reversely connected, and is multiplied with power frequency reactive power sign function
With transient reactive power, transient reactive power will be made to keep original numerical value, so using revised transient reactive power into
Row route selection.If revised transient reactive power is, then
；
If, then it represents that transient reactive power flows to the alternative outlet k of failure by bus, and the alternative outlet k of failure is
Sound circuit；If, then it represents that transient reactive power flows to bus, the alternative outlet k of failure by the alternative outlet k of failure
For faulty line；If all routes are all satisfied, then system is busbar grounding failure.
The ground fault of certain power supply enterprise 10kV aerial cable joint line system as shown in Figure 2, wherein outlet F4 is
The zero sequence TA error-polarity connection of faulty line, outlet F1 and outlet F3.When outlet F4 occur metallicity singlephase earth fault, according to
Lower step carries out route selection:
A. biggish 4 outlets of transient zero-sequence current Amplitude Ration are chosen as the alternative outlet of failure；
B. according to formulaCalculate choose 4 alternative outlets of failure transient state without
Function power, calculated result are as follows:
,,,；
C. according to formulaCalculate the idle function of power frequency for the 4 alternative outlets of failure chosen
Rate, calculated result are as follows:
,,,；
D. according to formulaThe revised transient state for calculating the 4 alternative outlets of failure chosen is idle
Power, calculated result are as follows:
,,,；
The revised transient reactive power direction outlet F4 in this way and other 3 outlet differences, according to provided by the invention
It is faulty line that a kind of synthetic power-frequency and the distribution network fault line selection method in transient reactive power direction, which can select outlet F4,
Eliminate the influence of outlet F1, outlet F3 sound circuit TA reversal connection.
The present invention is not limited to above-described specific embodiment, and the foregoing is merely preferable case study on implementation of the invention
, it is not intended to limit the invention, any modification done within the spirit and principles of the present invention and changes equivalent replacement
Into etc., it should all be included in the protection scope of the present invention.
Claims (2)
1. the distribution network fault line selection method of a kind of synthetic power-frequency and transient reactive power direction, it is characterised in that: including following
Step:
(1) zero-sequence current and bus residual voltage in each outlet bus exit of on-line acquisition system, when monitoring bus zero sequence
When voltage magnitude is more than pre-set bus residual voltage amplitude thresholds, illustrate that singlephase earth fault has occurred in system；
(2) the biggish n outlet of transient zero-sequence current Amplitude Ration is chosen as the alternative outlet of failure；Wherein n > 1；
(3) transient reactive power for the alternative outlet of n failure chosen in step (2) is calculated according to following formula:
；
Wherein, number of the k for the alternative outlet of failure, k=1,2, n；TFor the transient process duration,For failure
The transient zero-sequence current in the bus exit of alternative outlet k,For bus transient zero-sequence voltage；If, then table
Show that the transient reactive power of the alternative outlet k of failure flows to the alternative outlet k of failure by bus, the alternative outlet k of failure is sound circuit；
If, then it represents that the transient reactive power of the alternative outlet k of failure flows to bus by the alternative outlet k of failure, and failure is alternative
Outlet k is faulty line；If the faulty alternative outlet of institute is all satisfied, then system is busbar grounding failure；
(4) according to following formulaCalculate step (2) in choose faulty alternative outlet power frequency reactive power:
；
Wherein, number of the k for the alternative outlet of failure, k=1,2, n；For the zero-sequence current of the alternative outlet k of failure
Power frequency component,For bus residual voltage power frequency component,TFor the transient process duration；If, then it represents that
Power frequency reactive power flows to the alternative outlet k of failure by bus；If, then it represents that power frequency reactive power is alternatively gone out by failure
Line k flows to bus；
(5) transient reactive power of the alternative outlet of failure is modified using the power frequency reactive power of the alternative outlet of failure, so
More revised transient reactive power afterwards carries out route selection according to the direction of revised transient reactive power, if revised
Transient reactive power is, then
；
If, then it represents that transient reactive power flows to the alternative outlet k of failure by bus, and the alternative outlet k of failure is sound
Route；If, then it represents that transient reactive power flows to bus by the alternative outlet k of failure, and the alternative outlet k of failure is event
Hinder route；If all routes are all satisfied, then system is busbar grounding failure.
2. the distribution network fault line selection method of a kind of synthetic power-frequency and transient reactive power direction according to claim 1,
It is characterized by: choosing T in the step (4) is a power frequency period.
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| CN108287286B (en) * | 2018-01-16 | 2023-03-14 | 济南置真电气有限公司 | Polarity verification method based on single-phase earth fault recording data |
| CN109507525A (en) * | 2018-10-26 | 2019-03-22 | 国网江西省电力有限公司电力科学研究院 | A kind of earth-fault detecting method based on amendment transient reactive power method |
| CN109387742B (en) * | 2018-11-06 | 2020-07-24 | 华中科技大学 | Line fault identification method based on multipoint active power monitoring and difference |
| CN109387732A (en) * | 2018-12-21 | 2019-02-26 | 云南电网有限责任公司电力科学研究院 | A kind of adaptive in-situ protection method and system of small current grounding fault |
| CN110907758B (en) * | 2019-12-06 | 2021-10-22 | 国电南瑞科技股份有限公司 | Small current ground fault line selection method covering CT polarity self-correction |
| CN111766534B (en) * | 2020-06-07 | 2021-07-13 | 中车永济电机有限公司 | Traction converter ground fault detection method and device |
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