CN106384999A - Differential protection y-side phase-shift current phase compensation method for YNy2 transformer - Google Patents

Abstract

The invention discloses a differential protection y-side phase-shift current phase compensation method for a YNy2 transformer. Y-side and y-side of the YNy2 transformer eliminate zero-sequence current in phase current to prevent misoperation due to influence of zero-sequence current on differential protection of the transformer. For differential protection of the Yny2 transformer, phase compensation employs a y-side phase shift method based on Y-side reference, wherein the current phase compensation for Y side is conducted through a calculation method of eliminating zero sequence current by sequence phase current with the A-phase current as reference, and the y side of the Yny2 transformer employs a calculation method of eliminating zero sequence current by sequence phase current and conducts current phase compensation by the principles of same phase with y-side corresponding current. The method is applicable to software phase compensation for current of longitudinal differential protective devices of YNy2 wiring transformers with various voltage levels of substations of a power transmission and distribution network. The method is simple and clear and is easy to realize.

Description

YNy2 transformer differential protection y sidesway phase current phase compensating method

Technical field

The present invention relates to a kind of YNy2 transformer longitudinal linked differential protection eliminates zero-sequence current y sidesway phase current phase compensation side Method, belongs to the relay protection and control equipment technical field of electrical power distribution electric network.

Background technology

Because electric current possible phase place in transformer each side is inconsistent, therefore transformer longitudinal linked differential protection (hereinafter referred to as transformation Device differential protection) current phase compensate to be carried out.The method of transformer differential protection current phase compensate has two kinds：1. traditional Analog shifter：Such as current transformer TA Secondary Winding in YNd11 transformer Y side adopts triangle d-11 wiring, d side TA Secondary Winding Using star Y-12 wiring；2. digit shifter：Carry out electric current phase shift using software program and computing formula and complete phase place benefit Repay.At present, 220kV and above tranformer protection are generally main protection, back-up protection integrated design, duplicate system retrofit, main guarantor Shield, back-up protection integrated design be main protection and all of back-up protection all in a cabinet, using same hardware dress Put and software, transformer main protection, the electric current of the every side of back-up protection, voltage are all using current transformer TA, voltage transformer Same group of Secondary Winding.Because the tranformer protection current loop of main protection, back-up protection integration is the same electricity adopting Flow back to road, so current phase compensate can not be carried out using traditional analog shifter.The current transformer of the therefore each side of transformer TA must adopt star connection, carries out phase compensation using digit shifter.110kV and following microcomputer transformer differential protection are current Also current phase compensate is not carried out using traditional analog shifter, the TA of each side is typically also adopted by star connection, is also adopted by differential The electric current software of protection carries out phase compensation, and progressively to main protection back-up protection integrated design, double set configuration transition.But Be, at present each tranformer protection manufacturer only devise this several transformer connection group of YNd11, YNd1 and YNyn12 and its The differential protection current phase compensate method of wiring combination, does not design other wiring groups and the transformer of wiring combination mode Differential protection electric current software phase compensating method.The present invention will propose a kind of YNy2 transformer differential protection and eliminate zero-sequence current y Sidesway phase current Phase Compensation scheme.

Content of the invention

It is an object of the invention to provide a kind of YNy2 transformer differential protection y sidesway phase current phase compensating method, should For the various electric pressure main transformers of the various electric pressure electric substations of transmission and distribution networkses, complete YNy2 transformer longitudinal connection poor Dynamic protection eliminates the phase compensation of zero-sequence current y sidesway phase current.

The purpose of the present invention is achieved by the following technical programs：

A kind of YNy2 transformer differential protection y sidesway phase current phase compensating method, comprises the following steps：

Step 1：YNy2 high voltage side of transformer, low-pressure side current transformer TA Secondary Winding are all connected in star connection；

Step 2：On the basis of Y side, for Y side, because zero-sequence current to be eliminatedImpact to differential protection, so ginseng A phase current with differential protection differential current computingB phase currentC phase currentIt is respectively：

${\stackrel{\·}{I}}_{dA}={\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_0---\left(1\right)$

${\stackrel{\·}{I}}_{dB}={\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_0---\left(2\right)$

${\stackrel{\·}{I}}_{dC}={\stackrel{\·}{I}}_C-{\stackrel{\·}{I}}_0---\left(3\right)$

In above formulaFor the A phase current of transformer Y side participation differential current computing, B phase current, C phase current；For accessing the secondary current of the current transformer TA of transformer Y side A phase, B phase, C phase；Wherein,

Step 3：For y side, in order to make, y side participates in each phase current of differential protection differential current computing and Y side participates in differential protection Each phase current phase place of differential current computing is identical, the synchronous y side of current transformer TA secondary current with Y side A phase, B phase, C phase Current transformer TA secondary current is respectively-b phase ,-c phase ,-a phase, for eliminating zero-sequence currentImpact to differential protection, institute To participate in a phase current of differential protection differential current computingB phase streamWith c phase currentFor：

${\stackrel{\·}{I}}_{da}=-({\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_{y0})---\left(4\right)$

${\stackrel{\·}{I}}_{db}=-({\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_{y0})---\left(5\right)$

${\stackrel{\·}{I}}_{dc}=-({\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_{y0})---\left(6\right)$

In above formulaFor a phase after transformer y side phase compensation, b phase, c phase current； For Access transformer d side a phase, b phase, the current transformer TA secondary current of c phase, wherein,

The purpose of the present invention can also be realized further by following technical measures：

Aforementioned YNy2 transformer differential protection y sidesway phase current phase compensating method, applies also for Yy2 wiring and its connects The transformer of line combination.

Aforementioned YNy2 transformer differential protection y sidesway phase current phase compensating method, in based Transformer differential protection Application is run in device.

Aforementioned YNy2 transformer differential protection y sidesway phase current phase compensating method, in PLC type transformer differential protection dress Put middle operation to apply.

Aforementioned YNy2 transformer differential protection y sidesway phase current phase compensating method, described current transformer TA model LJZ series.

Compared with prior art, the invention has the beneficial effects as follows：YNy2 transformer Y side and y side are all using in phase current Eliminate zero-sequence current, prevent the misoperation that transformer differential protection produces because zero-sequence current affects.For Yny2 transformer Differential protection, phase compensation is the method adopting y sidesway phase on the basis of Y side, and wherein Y side is employed on the basis of A phase current The computational methods that order phase current eliminates zero-sequence current carry out current phase compensate, employ order for Yny2 transformer y side Phase current eliminates the computational methods of zero-sequence current and current in phase corresponding to y side ground principle carries out current phase compensate.

By above-mentioned phase transition, the transformer Y side of YNy2 wiring and y side is made to participate in differential protection each phase differential current computing A phase currentWith a phase currentPhase place is consistent, B phase currentWith b phase streamPhase place is consistent, C phase currentWith c phase currentPhase place is consistent.

Compared with the method used in existing based Transformer differential protection, the present invention is applied to power transmission and distribution The YNy2 wiring of network electric substation, the electric current software phase place of Yy2 wiring various electric pressure transformer longitudinal linked differential protection device are mended Repay technical scheme, and simply clear, easily realize.

Brief description

Fig. 1 is the YNy2 transformer connection figure of the present invention；

Fig. 2 is the vectogram after the YNy2 wiring transformer both sides electric current software compensation of the present invention.

Specific embodiment

The invention will be further described with specific embodiment below in conjunction with the accompanying drawings.

As shown in figure 1, being YNy2 transformer connection figure according to the present invention.

Because computer-based transformer protection is generally main protection back-up protection integrated design, duplicate system retrofit, transformer is poor Dynamic protection requires YNy2 high voltage side of transformer, low-pressure side TA Secondary Winding to be all connected in wye connection.YNy2 wiring transformer is differential The electric current software phase compensation scheme of protection device is：

(1) YNy2 high voltage side of transformer, low-pressure side TA Secondary Winding are all connected in wye connection.

(2) for Y side, because zero-sequence current to be eliminatedImpact to differential protection, so participate in differential protection difference stream The A phase current calculatingB phase currentC phase currentFor：

${\stackrel{\·}{I}}_{dA}={\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_0---\left(7\right)$

${\stackrel{\·}{I}}_{dB}={\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_0---\left(8\right)$

${\stackrel{\·}{I}}_{dC}={\stackrel{\·}{I}}_C-{\stackrel{\·}{I}}_0---\left(9\right)$

(7-9) in formulaFor the A phase current of device Y side participation differential current computing, B phase current, C phase current；TA secondary current for access device Y side A phase, B phase, C phase.Wherein,

(3) for y side, it is respectively-b with the A phase, B phase, C phase TA secondary current synchronous y side TA secondary current of Y side Phase ,-c phase ,-a phase, and because zero-sequence current to be eliminatedImpact to differential protection, so participate in differential protection differential current computing A phase currentB phase streamWith c phase currentFor：

${\stackrel{\·}{I}}_{da}=-({\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_{y0})---\left(10\right)$

${\stackrel{\·}{I}}_{db}=-({\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_{y0})---\left(11\right)$

${\stackrel{\·}{I}}_{dc}=-({\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_{y0})---\left(12\right)$

(10-12) in formulaFor a phase after device y side software phase compensation, b phase, c phase current；For access device d side a phase, b phase, c phase TA secondary current.Wherein,

(4) by above-mentioned phase transition, the transformer Y side of YNy2 wiring and y side is made to participate in differential protection and respectively differ flowmeter The A phase current calculatedWith a phase currentPhase place is consistent, B phase currentWith b phase streamPhase place is consistent, C phase currentWith c phase Electric currentPhase place is consistent.

(5) adopt the transformer Y side of YNy2 wiring and y side all to eliminate zero-sequence current using phase differential current, prevent transformer The misoperation that differential protection produces because zero-sequence current affects；The current phase compensate of transformer differential protection adopts Y side phase Position compensation method.

Vectogram behind Y side and y side current compensation is as shown in Fig. 2 Fig. 2 (a) is for after the current compensation of Y side Vectogram, Fig. 2 (b) is the vectogram after the current compensation of y side.In Fig. 2

In addition to the implementation, the present invention can also have other embodiment, all employing equivalents or equivalent transformation shape The technical scheme becoming, all falls within the protection domain of application claims.

Claims (5)

1. a kind of YNy2 transformer differential protection y sidesway phase current phase compensating method is it is characterised in that comprise the following steps：

Step 1：YNy2 high voltage side of transformer, low-pressure side current transformer TA Secondary Winding are all connected in star connection；

Step 2：On the basis of Y side, for Y side, because zero-sequence current to be eliminatedImpact to differential protection, so participation is poor The A phase current of dynamic protection differential current computingB phase currentC phase currentIt is respectively：

${\stackrel{\·}{I}}_{dA}={\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_0---\left(1\right)$

${\stackrel{\·}{I}}_{dB}={\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_0---\left(2\right)$

${\stackrel{\·}{I}}_{dC}={\stackrel{\·}{I}}_C-{\stackrel{\·}{I}}_0---\left(3\right)$

In above formulaFor the A phase current of transformer Y side participation differential current computing, B phase current, C phase current；For accessing the secondary current of the current transformer TA of transformer Y side A phase, B phase, C phase；Wherein,

Step 3：For y side, in order to make, y side participates in each phase current of differential protection differential current computing and Y side participates in differential protection difference stream The each phase current phase place calculating is identical, the current transformer TA secondary current synchronous y side electric current with Y side A phase, B phase, C phase Transformer TA secondary current is respectively-b phase ,-c phase ,-a phase, for eliminating zero-sequence currentImpact to differential protection, so ginseng A phase current with differential protection differential current computingB phase streamWith c phase currentFor：

${\stackrel{\·}{I}}_{da}=-({\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_{y0})---\left(4\right)$

${\stackrel{\·}{I}}_{db}=-({\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_{y0})---\left(5\right)$

${\stackrel{\·}{I}}_{dc}=-({\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_{y0})---\left(6\right)$

In above formulaFor a phase after transformer y side phase compensation, b phase, c phase current； For accessing Transformer d side a phase, b phase, the current transformer TA secondary current of c phase, wherein,

2. YNy2 transformer differential protection y sidesway phase current phase compensating method as claimed in claim 1 it is characterised in that Can be applicable to the transformer of Yy2 wiring and its wiring combination.

3. YNy2 transformer differential protection y sidesway phase current phase compensating method as claimed in claim 1 it is characterised in that Application is run in based Transformer differential protection.

4. YNy2 transformer differential protection y sidesway phase current phase compensating method as claimed in claim 1 it is characterised in that Application is run in PLC type differential protective device of transformer.

5. YNy2 transformer differential protection y sidesway phase current phase compensating method as claimed in claim 1 it is characterised in that Described current transformer TA model LJZ series.