CN101895103B - Composite detecting impedence-based distance protection setting method - Google Patents

Abstract

The invention discloses a kind of distance protection setting method based on composite detecting impedence, adaptive setting formula are as follows: ZDZ is the action impedance of protection to be adjusted; Kk is safety factor; when U φ 1, I φ 1, I01, I ' φ 1 and I ' 01 are respectively line end failure where mating protection, protect the phase voltage of installation place, phase current, zero-sequence current and mating protection installation place phase current, zero-sequence current; K and K ' is respectively the zero-utility theory of route where route where protecting and mating protection; Z ' DZ is the action impedance of mating protection; Z ' L is route positive sequence impedance where mating protection. The present invention has comprehensively considered influence of the factors such as positive zero-sequence network difference, zero-sequence mutual inductance to adaptive setting, and adjusting result is reasonable; This method can optimize protection definite value, and improve the overall operation performance of protection system.

Description

A kind of distance protection setting method based on composite detecting impedence

Technical field

The invention belongs to AC transmission system technical field of relay protection, be specifically related to a kind of distance protection setting method based on composite detecting impedence.

Background technology

Ground distance protection is a kind of impedance protection of low actuating quantity, and according to presence or absence and the distance of the size failure judgement of protection installation place measurement impedance, its maximum feature is exactly that protection range affects little by changes of operating modes, relatively fixing.Along with the development of Microcomputer Protection technology, the application of ground distance protection in supergrid is increasingly extensive, has become topmost earth fault backup protection.

At present, ground distance protection adaptive setting generally have employed based on helping the setting method increasing coefficient ^[1].Matching relationship between protection is converted to mating protection place circuit and the proportionate relationship protecting place line current by the method; be called and help increasing coefficient, be multiplied by help and increase coefficient sum by calculating protection place line impedance and mating protection action impedance and obtain and protect definite value.

Based on helping the tuning formulae increasing coefficient such as formula shown in (1):

Z _DZ＝K _kZ _L+K _kK _ZZ′ _DZ (1)

Wherein, Z _dZfor waiting the action impedance protected of adjusting; K _kfor safety factor; K _zcoefficient is increased and zero sequence helps the smaller value increased in coefficient for protection and mating protection positive sequence during mating protection protection range end fault help; Z _lfor protection place circuit positive sequence impedance; Z ' _dZfor mating protection action impedance.。The weak point of the method is just being have ignored, the difference of zero-sequence network and the impact of zero-sequence mutual inductance, and result of calculation is not accurate enough in some cases; And introduce protection place line impedance in its tuning formulae, when being applied to some ad hoc network, formula form may change with network configuration and system running state change, and computer realizes complicated.

For based on helping the deficiency increasing coefficient setting method, document [2,3] have studied the setting method based on detecting impedence, and its basic thought is directly according to protecting the experience impedance of installation place to calculate protection definite value during mating protection end fault.The method has considered the factors such as positive zero-sequence network difference, zero-sequence mutual inductance to the impact of adaptive setting, ensure that the accuracy of result of adjusting.The setting method based on detecting impedence that document [3] proposes is as follows:

1) when protecting place circuit to be without zero-sequence mutual inductance circuit, tuning formulae is such as formula shown in (2).

$Z_{\mathrm{DZ}}=K_k{Z}_L+K_k\frac{I_{\mathrm{\φ}}^{\′}+{3K}^{\′}{I}_0^{\′}}{I_{\mathrm{\φ}}+{3\mathrm{KI}}_0}\·Z_{\mathrm{DZ}}^{\′}---\left(2\right)$

2) when protecting place circuit to be zero-sequence mutual inductance circuit, tuning formulae is such as formula shown in (3).

$Z_{\mathrm{DZ}}=K_k{Z}_L+K_k(\frac{U_{\mathrm{\φ}}}{I_{\mathrm{\φ}}+{3\mathrm{KI}}_0}-Z_L)\·\frac{1}{Z_L^{\′}}{Z}_{\mathrm{DZ}}^{\′}---\left(3\right)$

Wherein, I _φ, I ₀, K, I ' _φ, I ' ₀, when K ' is respectively mating protection place line end fault, the phase current of protection installation place, zero-sequence current, the phase current of zero-utility theory and mating protection installation place, zero-sequence current, zero-utility theory; Z _l, Z ' _lfor protection place circuit and mating protection place circuit positive sequence impedance; Z ' _dZfor mating protection action impedance.Owing to introducing protection place line impedance in tuning formulae equally, also there is the deficiency that formula form may change with network configuration and system running state change.

List of references:

[1] The National Electric Power Communication Center. relay protection of power system regulation compilation. Beijing: China Electric Power Publishing House, 1997.82 ~ 83.

[2] Wang Zhenzhen, Ling Xu, Li Xiaojuan etc. Power System Intelligent type program of ground distance protection [J]. Automation of Electric Systems, 2000,24 (16): 55-57.

Wang Zhenzhen,Ling Xu,Li Xiaojuan.The Intelligent Program Of Power System Ground Distance Protection Automation Of Electric Power Systems.Automation of Electric Power Systems[J],2000,24(16)：55-57(in Chinese).

[3] Wang Guangxue, the pay tinkling of pieces of jade, Li Xiaojuan. power system transmission line ground distance protection adaptive setting research [J]. electric power network technique, 2002,26 (2): 50-53.

Wang Guangxue,Feng Ling,Li Xiaojuan.Research On Setting Calculation Of Grounding Distance Protection Of Transmission[J].Power System Technology,2002,26(2)：50-53(in Chinese).

Summary of the invention

The object of the present invention is to provide a kind of coordinating and setting distance protections method based on composite detecting impedence, the method can optimize protection definite value, and improves the overall operation performance of protection system.

The invention provides a kind of distance protection setting method based on composite detecting impedence, the adaptive setting formula that the method adopts is such as formula shown in (4):

$Z_{\mathrm{DZ}}=K_k\frac{U_{\mathrm{\φ}1}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}+K_k\frac{I_{\mathrm{\φ}1}^{\′}+{3K}^{\′}{I}_{01}^{\′}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}(Z_{\mathrm{DZ}}^{\′}-Z_L^{\′})$ Formula (4)

Wherein, Z _dZfor waiting the action impedance protected of adjusting, K _kfor safety factor, U _{φ 1}, I _{φ 1}and I ₀₁when being respectively mating protection place line end fault, protect the phase voltage of installation place, phase current and zero-sequence current, I ' _{φ 1}with I ' ₀₁when being respectively mating protection place line end fault, the phase current of mating protection installation place and zero-sequence current; K and K ' is respectively the zero-utility theory of protection place circuit and mating protection place circuit; Z ' _dZfor the action impedance of mating protection; Z ' _lfor mating protection place circuit positive sequence impedance.

The present invention is directed to based on helping the deficiency increasing coefficient setting method, proposing practical setting principle.Compared with existing setting method, the improvement setting method based on detecting impedence has the following advantages:

1) considered the factors such as positive zero-sequence network difference, zero-sequence mutual inductance to the impact of adaptive setting, result of adjusting is reasonable;

2) tuning formulae unity of form, for any mating protection, as vertical, distance I, II, III section etc., can determine to protect definite value easily;

3) tuning formulae does not introduce protection place line impedance; only relevant with the voltage of protection position, the magnitude of current and the mating protection position magnitude of current, mating protection action impedance; formula form does not change by network topology structure and element running status to be affected, and is conducive to computer and realizes.

Accompanying drawing explanation

Fig. 1 is the flow chart of the inventive method;

Fig. 2 is certain large-scale ultrahigh pressure electrical network local topology figure.

Embodiment

The present invention first analysed in depth that present ground distance protection adaptive setting generally adopts based on helping the setting method increasing coefficient, summarize the deficiency of this setting method.Then, by existing based on based on the setting method of detecting impedence, propose the improvement setting method based on detecting impedence, give generally be suitable for, the adaptive setting formula of unity of form.Finally, in Practical Project example, increase coefficient setting method to based on helping and compare based on the result of adjusting of detecting impedence improvement setting method, comparative result demonstrates the validity of improving one's methods.

As shown in Figure 1, the inventive method comprises the steps:

1) based on the thought of adjusting of detecting impedence, the experience impedance of installation place during mating protection protection range end fault, is protected to be protection definite value, shown in (5).

$Z_{\mathrm{DZ}}=K_k\frac{U_{\mathrm{\φ}}}{I_{\mathrm{\φ}}+{3\mathrm{KI}}_0}---\left(5\right)$

Wherein, U _φ, I _φ, I ₀when being respectively mating protection protection range end fault, the phase voltage of protection installation place, phase current and zero-sequence current; K protects the zero-utility theory of place circuit.

2) apply the phase voltage of principle of stacking to protection installation place to decompose, be decomposed into the voltage drop of protection place circuit and the phase voltage of mating protection installation place, carry out equivalence transformation, simultaneously shown in (6).

$Z_{\mathrm{DZ}}=K_k\frac{{\mathrm{\ΔU}}_{\mathrm{\φ}}}{I_{\mathrm{\φ}}+{3\mathrm{KI}}_0}+K_k\frac{I_{\mathrm{\φ}}^{\′}+{3K}^{\′}{I}_0^{\′}}{I_{\mathrm{\φ}}+{3\mathrm{KI}}_0}{Z}_{\mathrm{DZ}}^{\′}---\left(6\right)$

Wherein, Δ U _φ, I ' _φ, I ' ₀when being respectively mating protection protection range end fault, the voltage drop of protection place circuit and the phase current of mating protection installation place, zero-sequence current; K and K ' is respectively the zero-utility theory of protection place circuit and mating protection place circuit; Z ' _dZfor mating protection action impedance.

3) two hypothesis extensively adopted in engineering are introduced:

1. when mating protection place line end fault and mating protection protection range end fault, protection place circuit I _φ+ 3KI ₀with mating protection place circuit I ' _φ+ 3K ' I ' ₀ratio identical.

2. when mating protection place line end fault and mating protection protection range end fault, protection place line electricity pressure drop Δ U _{φ 1}with recombination current I _φ+ 3KI ₀ratio identical.

Carrying out conversion to formula (6) obtains formula (7) to utilize these two to suppose:

$Z_{\mathrm{DZ}}=K_k\frac{{\mathrm{\ΔU}}_{\mathrm{\φ}1}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}+K_k\frac{I_{\mathrm{\φ}1}^{\′}+{3K}^{\′}{I}_{01}^{\′}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}{Z}_{\mathrm{DZ}}^{\′}---\left(7\right)$

Wherein, U _{φ 1}, I _{φ 1}, I ₀₁, I ' _{φ 1}, I ' ₀₁when being respectively mating protection place line end fault, the phase voltage of protection installation place, phase current, the phase current of zero-sequence current and mating protection installation place, zero-sequence current; K and K ' is respectively the zero-utility theory of protection place circuit and mating protection place circuit; Z ' _dZfor mating protection action impedance.

4), during mating protection place line end fault, the phase voltage of the application addition method to protection installation place is decomposed.Conversion is carried out to formula (6) and obtains formula (8):

$K_k\frac{U_{\mathrm{\φ}1}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}=K_k\frac{{\mathrm{\ΔU}}_{\mathrm{\φ}1}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}+K_k\frac{I_{\mathrm{\φ}1}^{\′}+{3K}^{\′}{I}_{01}^{\′}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}{Z}_L^{\′}---\left(8\right)$

5) according to formula (7) and formula (8) derive with network configuration and system operation mode change, unity of form and be easy to realize adaptive setting formula, shown in (9):

$Z_{\mathrm{DZ}}=K_k\frac{U_{\mathrm{\φ}1}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}+K_k\frac{I_{\mathrm{\φ}1}^{\′}+{3K}^{\′}{I}_{01}^{\′}}{I_{\mathrm{\φ}1}+{3\mathrm{KI}}_{01}}(Z_{\mathrm{DZ}}^{\′}-Z_L^{\′})---\left(9\right)$

Wherein, U _{φ 1}, I _{φ 1}, I ₀₁, I ' _{φ 1}, I ' ₀₁when being respectively mating protection place line end fault, the phase voltage of protection installation place, phase current, the phase current of zero-sequence current and mating protection installation place, zero-sequence current; K and K ' is respectively the zero-utility theory of protection place circuit and mating protection place circuit; Z ' _dZfor mating protection action impedance; Z ' _lfor mating protection place circuit positive sequence impedance.

Below by instantiation, technical scheme of the present invention is further stated.

For large-scale ultrahigh pressure electric power system shown in accompanying drawing 2, adopt respectively based on helping the setting method of increasing coefficient and adjusting to 500kV line-to-ground distance protection II sections all in system based on the improvement setting method of detecting impedence, adjusting, the results are shown in Table 1.

Table 1 helps to increase coefficient setting method and improve detecting impedence setting method and to adjust result

As can be seen from Table 1, and increase compared with coefficient setting method based on helping, improve based on detecting impedence the result sensitivity of adjusting that setting method obtains and improve, operate time shortens, and optimizes the protection definite value level of whole system.

(1) employing is improved one's methods, and the definite value sensitivity of most of protection improves, the protections such as white, the clear thread-changing of line is changed as struggled against in vain in table, Yun Xian hilllock, hilllock, five people's lines five, Pueraria lobota two-wire Pueraria lobota, Zheng's Yao line Zheng;

(2) employing is improved one's methods; part protection coordinates can meet sensitivity requirement with lower section of mating protection; the protections such as husky in the line bucket that struggles against in vain, two, the multiple husky line of double blank I, two beautiful II is two, five people's line people, shorten operate time, improve the protection definite value level of whole system.

(3) between Gezhouba Hydropower Plant and current conversion station be the short-term road that twice length is only 3.5 kilometers, the protection of Ge Gang line Pueraria lobota is crossed over this two loop line and is directly changed protection with clear thread-changing and coordinate.Adopt based on help increase coefficient setting method adjust the protection of Ge Gang line Pueraria lobota time, tuning formulae changes two loop line running statuses changes with Pueraria lobota and changes, and adaptive setting is complicated; And employing is improved one's methods, tuning formulae is only current related with protection part voltage, electric current and mating protection place, and adaptive setting is simple.

The present invention is not limited to above-mentioned embodiment; persons skilled in the art are content disclosed in example and accompanying drawing; other multiple embodiment can be adopted to implement the present invention; therefore; every employing project organization of the present invention and thinking; do the design that some simply change or change, all fall into the scope of protection of the invention.

Claims (1)

1., based on a distance protection setting method for composite detecting impedence, the adaptive setting formula that the method adopts is such as formula shown in I:

$Z_{\mathrm{DZ}}=K_k\frac{U_{\mathrm{\φ}1}}{I_{\mathrm{\φ}1}+3{\mathrm{KI}}_{01}}+K_k\frac{I_{\mathrm{\φ}1}^{\′}+3K^{\′}{I}_{01}^{\′}}{I_{\mathrm{\φ}1}+2{\mathrm{KI}}_{01}}(Z_{\mathrm{DZ}}^{\′}-Z_L^{\′})$ Formula I

Wherein, Z _dZfor waiting the action impedance protected of adjusting, K _kfor safety factor, U _{φ 1}, I _{φ 1}and I ₀₁when being respectively mating protection place line end fault, protect the phase voltage of installation place, phase current and zero-sequence current, I ' _{φ 1}with I ' ₀₁when being respectively mating protection place line end fault, the phase current of mating protection installation place and zero-sequence current; K and K ' is respectively the zero-utility theory of protection place circuit and mating protection place circuit; Z ' _dZfor the action impedance of mating protection; Z ' _lfor mating protection place circuit positive sequence impedance.