CN106385003A - y-side differential protection current zero sequence phase eliminating compensation method for YNy2 transformer - Google Patents

Abstract

The invention discloses a y-side differential protection current zero sequence phase eliminating compensation method for a YNy2 transformer. The method includes the steps of using Y-connection means for connecting TA secondary windings of high-voltage side and low-voltage side current transformers of the YNy2 transformer, firstly obtaining Y-side zero sequence eliminating current participating in differential protection calculation, conducting software phase shift and phase compensation for y-side current participating in differential protection calculation according to Y-side phase compensation principles based on the obtained phase of the Y-side current participating in differential protection calculation to obtain the phase of the y-side current participating in differential protection calculation consistent with the phase of the Y-side current participating in differential protection calculation. Rapid and convenient current phase compensation for differential protection of a YNy2 transformer can be realized through a software phase shift method. The method is applicable to software phase compensation for current of longitudinal differential protective devices of YNy2 wiring and Yy2 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 y side differential protection electric current zero suppression sequence phase compensating method

Technical field

The present invention relates to a kind of YNy2 transformer y side differential protection electric current zero suppression sequence phase compensating method, belong to electric power defeated The relay protection and control equipment technical field of distribution 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 y side poor Dynamic protection eliminates the phase compensation of zero-sequence current.

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

A kind of YNy2 transformer y side differential protection electric current zero suppression sequence 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：Zero-sequence current in every electric current of Y side participation differential protection Current calculation is eliminated by below equation, And phase transition；

${\stackrel{\·}{I}}_{dA}=({\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_B)/\sqrt{3}$

${\stackrel{\·}{I}}_{dB}=({\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_C)/\sqrt{3}$

${\stackrel{\·}{I}}_{dC}=({\stackrel{\·}{I}}_C-{\stackrel{\·}{I}}_A)/\sqrt{3}$

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；

Step 3：Based on after phase transition described in step 2 Y side participate in differential protection Current calculation every electric current to Amount, the every electric current participating in differential protection Current calculation to y side carries out phase transition, makes y side participate in the electricity that differential protection calculates The current phase that stream phase place participates in differential protection calculating with Y side is consistent, completes current phase compensate.

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

Aforementioned YNy2 transformer y side differential protection electric current zero suppression sequence phase compensating method, is participated in y side by equation below Every electric current of differential protection Current calculation carries out phase transition；

${\stackrel{\·}{I}}_{da}=({\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b)/\sqrt{3}$

${\stackrel{\·}{I}}_{db}=({\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_c)/\sqrt{3}$

${\stackrel{\·}{I}}_{dc}=({\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_a)/\sqrt{3}$

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

Aforementioned YNy2 transformer y side differential protection electric current zero suppression sequence phase compensating method, in the differential guarantor of based Transformer Application is run in protection unit.

Aforementioned YNy2 transformer y side differential protection electric current zero suppression sequence phase compensating method, in PLC type transformer differential protection Application is run in device.

Aforementioned YNy2 transformer y side differential protection electric current zero suppression sequence phase compensating method, described current transformer TA model For LJZ series.

Compared with prior art, the invention has the beneficial effects as follows：YNy2 transformer Y side, using eliminating zero-sequence current, can be prevented The misoperation only being produced due to zero-sequence current impact during transformer differential protection, Y side adopts the phase transition formula can one Step completes zero-sequence current and eliminates and phase transition function.

For YNy2 transformer differential protection, phase compensation procedure, using Y side as benchmark, carries out current phase benefit to y side Repay, wherein with order to the phase transition carrying out every electric current, y side is using backward to carrying out every current phase conversion simultaneously for Y side Ground identical with Y side phase induced current principle carries out current phase compensate.Y side also can a step be completed to phase transition formula by backward Zero-sequence current eliminates and phase transition function, is produced due to zero-sequence current impact during preventing transformer differential protection Misoperation.

By above-mentioned phase transition so that YNy2 transformer Y side participates in the A phase current of differential protection differential current computing with y sideWith a phase currentPhase place is consistent, B phase currentWith b phase streamPhase place is consistent, C phase currentWith c phase currentPhase place Unanimously.

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 transformer Y side electric current software compensation of the present invention；

Fig. 3 is the vectogram after the YNy2 transformer y side 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.

In order to adapt to the configuration of main protection back-up protection integration, we are to YNy2 high voltage side of transformer, low-pressure side TA bis- Secondary winding is connected with star connection.YNy2 transformer y side differential protection electric current zero suppression sequence phase compensation scheme is：

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

Zero-sequence current in every electric current of Y side participation differential protection Current calculation, Yi Jixiang are eliminated by below equation Position conversion；

${\stackrel{\·}{I}}_{dA}=({\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_B)/\sqrt{3}---\left(1\right)$

${\stackrel{\·}{I}}_{dB}=({\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_C)/\sqrt{3}---\left(2\right)$

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

(1-3) in formulaElectric for the A phase current of transformer Y side participation differential current computing, B phase current, C phase Stream；For accessing the secondary current of the current transformer TA of transformer Y side A phase, B phase, C phase.(1-3) formula has been Directly the Current Transformer Secondary electric current zero-sequence current that may be present of Y side A phase, B phase and C phase is eliminated, prevent transformer The misoperation that differential protection produces because zero-sequence current affects.

Participate in every current vector of differential protection Current calculation based on the Y side after phase transition, differential guarantor is participated in y side Every electric current of shield Current calculation carries out phase transition, makes the current phase of y side participation differential protection calculating and the participation of Y side differential The current phase that protection calculates is consistent, completes current phase compensate.

Phase transition is carried out by every electric current that equation below participates in differential protection Current calculation to y side；

${\stackrel{\·}{I}}_{da}=({\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b)/\sqrt{3}---\left(4\right)$

${\stackrel{\·}{I}}_{db}=({\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_c)/\sqrt{3}---\left(5\right)$

${\stackrel{\·}{I}}_{dc}=({\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_a)/\sqrt{3}---\left(6\right)$

(4-6) in formulaFor a phase after transformer y side phase compensation, b phase, c phase current；For accessing the current transformer TA secondary current of transformer y side a phase, b phase, c phase.Equally (4-6) formula is straight Connect and the Current Transformer Secondary electric current zero-sequence current that may be present of Y side A phase, B phase and C phase is eliminated, prevent transformer poor The misoperation that dynamic protection is produced due to zero-sequence current impact.

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

As shown in Figure 2 and Figure 3, Fig. 2 is the vectogram after the current compensation of Y side to vectogram behind Y side and y side current compensation, figure 3 is the vectogram after the current compensation of y side, wherein

Because the molecular moiety in formula is that vector is calculated in direction, and vector does not only have direction and has specifically yet Amplitude.Equal if necessary to both members, then not only it is consistent on direction, also identical in amplitude, through calculation, Divided by radical sign 3, denominator can ensure that both members are all identical on direction with amplitude.

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 y side differential protection electric current zero suppression sequence phase compensating method is it is characterised in that include following walking Suddenly：

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

Step 2：Zero-sequence current in every electric current of Y side participation differential protection Current calculation is eliminated by below equation, and Phase transition；

${\stackrel{\·}{I}}_{dA}=({\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_B)/\sqrt{3}$

${\stackrel{\·}{I}}_{dB}=({\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_C)/\sqrt{3}$

${\stackrel{\·}{I}}_{dC}=({\stackrel{\·}{I}}_C-{\stackrel{\·}{I}}_A)/\sqrt{3}$

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；

Step 3：Participate in every current vector of differential protection Current calculation based on the Y side after phase transition described in step 2, right Every electric current that y side participates in differential protection Current calculation carries out phase transition, makes y side participate in the current phase that differential protection calculates Consistent with the current phase that Y side participates in differential protection calculating, complete current phase compensate.

2. YNy2 transformer y side as claimed in claim 1 differential protection electric current zero suppression sequence phase compensating method, its feature exists In, by equation below to y side participate in differential protection Current calculation every electric current carry out phase transition；

${\stackrel{\·}{I}}_{da}=({\stackrel{\·}{I}}_c-{\stackrel{\·}{I}}_b)/\sqrt{3}$

${\stackrel{\·}{I}}_{db}=({\stackrel{\·}{I}}_a-{\stackrel{\·}{I}}_c)/\sqrt{3}$

${\stackrel{\·}{I}}_{dc}=({\stackrel{\·}{I}}_b-{\stackrel{\·}{I}}_a)/\sqrt{3}$

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

3. YNy2 transformer y side as claimed in claim 1 or 2 differential protection electric current zero suppression sequence phase compensating method, its feature It is, based Transformer differential protection runs application.

4. YNy2 transformer y side as claimed in claim 1 or 2 differential protection electric current zero suppression sequence phase compensating method, its feature It is, PLC type differential protective device of transformer runs application.

5. YNy2 transformer y side as claimed in claim 1 or 2 differential protection electric current zero suppression sequence phase compensating method, its feature It is, described current transformer TA model LJZ series.