CN105024348A - D-side current phase compensation method for YNd5 transformer longitudinal differential protection - Google Patents

Abstract

The invention discloses a d-side current phase compensation method for YNd5 transformer longitudinal differential protection. The method is characterized by connecting the high-voltage side TA secondary winding and the low-voltage side TA secondary winding of an YNd5 transformer both in a star connection manner and performing current phase compensation on the d side of the YNd5 transformer. The method has beneficial effects of being a current phase software compensation technology scheme suitable for transformer longitudinal differential protection devices with various voltage classes for YNd5 wiring in a power transmission and distribution network power station, being simple and clear, and being easy to implement.

Description

YNd5 transformer longitudinal linked differential protection d side current phase compensation method

Technical field

The invention belongs to the relay protection and control technology of electrical power distribution electric network, relate to a kind of YNd5 transformer longitudinal linked differential protection d side current phase compensation method.

Background technology

Because transformer each side electric current possibility phase place is inconsistent, therefore transformer longitudinal linked differential protection (hereinafter referred to as transformer differential protection) will carry out current phase compensation.The method that transformer differential protection current phase compensates has two kinds: 1. traditional analog shifter: such as YNd11 transformer Y side current transformer (hereinafter referred to as TA) secondary winding adopts triangle d-11 wiring, d side TA secondary winding adopts star Y-12 wiring; 2. digit shifter: namely utilize software program and computing formula to carry out electric current phase shift to complete phase compensation.At present; 220kV and above tranformer protection are generally main protection backup protection integrated design, duplicate system retrofit; main protection backup protection integrated design is main protection and all backup protections all use same hardware and software in a cabinet, and the electric current of the every side of transformer main protection backup protection, voltage are all the secondary winding adopting TA, same group of voltage transformer.Because main protection backup protection integrated transformer protective current loop is the same current circuit adopted, traditional analog shifter therefore can not be adopted to carry out current phase compensation.The TA of each side of transformer must adopt wye connection, adopts electric current digit shifter to carry out phase compensation.110kV and following microcomputer transformer differential protection do not adopt traditional analog shifter to carry out current phase compensation at present yet; the TA of each side generally also adopts wye connection; also the electric current software phase compensation of differential protection is adopted, and progressively to main protection backup protection integrated design, two coverization configuration transition.But current each tranformer protection manufacturer only devises this several transformer connection group of YNd11, YNd1 and YNyn12 and wiring combination differential protection electric current software phase compensating method thereof, does not design the transformer differential protection electric current software phase compensating method of other wiring groups and wiring compound mode.Application number be 201210452816.9,201310186543.2,201410461437.5 and 201510109825.1 patent documentation propose the compensation method of 4 kinds of YNd5 transformer longitudinal linked differential protection current phases, be the technical scheme adopting hardware compensating and software compensation to combine.

Summary of the invention

The object of the present invention is to provide a kind of YNd5 transformer longitudinal linked differential protection d side current phase compensation method; meet transformer differential protection current phase compensation principle; principle is simple, enforcement is convenient, can adapt to the technical requirement that various electric pressure YNd5 transformer differential protection d sides current phase compensates.

Object of the present invention is achieved by the following technical programs:

A kind of YNd5 transformer longitudinal linked differential protection d side current phase compensation method, comprising:

(1) YNd5 high voltage side of transformer, low-pressure side TA secondary winding are all connect as wye connection, carry out current phase compensation in YNd5 transformer d side;

(2) for transformer Y side, because will zero-sequence current be eliminated on the impact of differential protection, so the electric current participating in differential protection differential current computing is:

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

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

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

In above formula for transformer Y side participates in A phase current, B phase current, the C phase current of differential current computing; for the TA secondary current of access transformer Y side A phase, B phase, C phase, wherein, ${\stackrel{\·}{I}}_0=({\stackrel{\·}{I}}_A+{\stackrel{\·}{I}}_B+{\stackrel{\·}{I}}_C)/3;$

(3) in transformer d side, phase transition is carried out by following formula:

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

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

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

In above formula for a phase after phase compensation, b phase, c phase current are carried out in transformer d side; for the TA secondary current of access transformer d side a phase, b phase, c phase;

(4) by above-mentioned phase transition, make the transformer d side current phase of YNd11 wiring consistent with Y side current phase.

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

Aforementioned YNd5 transformer longitudinal linked differential protection d side current phase compensation method, wherein the model of high voltage side of transformer, low-pressure side TA is LJZ series.

Aforementioned YNd5 transformer longitudinal linked differential protection d side current phase compensation method, wherein the model of high voltage side of transformer, low-pressure side TA is LCZ series.

Aforementioned YNd5 transformer longitudinal linked differential protection d side current phase compensation method, wherein the model of high voltage side of transformer, low-pressure side TA is LGBJ series.

Aforementioned YNd5 transformer longitudinal linked differential protection d side current phase compensation method, wherein the model of high voltage side of transformer, low-pressure side TA is LZ2B9 series.

Compared with prior art, the invention has the beneficial effects as follows: the current phase software compensation technique scheme being applicable to transmission and distribution networks electric substation YNd5 wiring various electric pressure transformer longitudinal linked differential protection device; Compensation method is simply clear, easily realizes.

Accompanying drawing explanation

Fig. 1 is YNd5 transformer connection figure of the present invention;

Fig. 2 is the vectogram after YNd5 wiring transformer both sides of the present invention electric current carries out phase compensation.

Embodiment

Below in conjunction with the drawings and specific embodiments, the invention will be further described.

YNd5 transformer connection figure of the present invention as shown in Figure 1.Because computer-based transformer protection is generally main protection backup protection integrated design, duplicate system retrofit, transformer differential protection requires YNd5 serial transformer high-pressure side, low-pressure side TA secondary winding all connects as wye connection.The electric current software phase compensation scheme of YNd5 wiring transformer differential protection is:

(1) YNd5 transformer d side is adopted to carry out current phase compensation.

(2) for Y side, because will zero-sequence current be eliminated on the impact of differential protection, so the electric current participating in differential protection differential current computing is:

${\stackrel{\·}{I}}_{\mathrm{dA}}={\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_0$

${\stackrel{\·}{I}}_{\mathrm{dB}}={\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_0$

${\stackrel{\·}{I}}_{\mathrm{dC}}={\stackrel{\·}{I}}_C-{\stackrel{\·}{I}}_0$

In above formula for device Y side participates in A phase current, B phase current, the C phase current of differential current computing; for the TA secondary current of access device Y side A phase, B phase, C phase.Wherein, ${\stackrel{\·}{I}}_0=({\stackrel{\·}{I}}_A+{\stackrel{\·}{I}}_B+{\stackrel{\·}{I}}_C)/3.$

(3) for d side, phase transition is carried out by following formula:

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

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

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

In above formula for a phase, b phase, c phase current after the phase compensation of device d side software; for the TA secondary current of access device d side a phase, b phase, c phase.

(4) by above-mentioned phase transition, make the transformer d side current phase of YNd11 wiring consistent with Y side current phase.

YNd5 high voltage side of transformer of the present invention, low-pressure side TA can select following model: LJZ is serial, LCZ is serial, LGBJ is serial, LZ2B9 is serial.

Vectogram after Y side and d side current compensation is shown in Fig. 2.In Fig. 2 fig. 2 (a) is the vectogram after the current compensation of Y side, and Fig. 2 (b) is the vectogram after the current compensation of d side.By phase transition, make the transformer d side current phase of YNd11 wiring consistent with Y side current phase.

In addition to the implementation, the present invention can also have other execution modes, and all employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop in the protection range of application claims.

Claims (5)

1. a YNd5 transformer longitudinal linked differential protection d side current phase compensation method, is characterized in that, comprising:

(1) YNd5 high voltage side of transformer, low-pressure side TA secondary winding are all connect as wye connection, carry out current phase compensation in YNd5 transformer d side;

(2) for transformer Y side, the electric current participating in differential protection differential current computing is:

${\stackrel{.}{I}}_{\mathrm{dA}}={\stackrel{.}{I}}_A-{\stackrel{.}{I}}_0$

${\stackrel{.}{I}}_{\mathrm{dB}}={\stackrel{.}{I}}_B-{\stackrel{.}{I}}_0$

${\stackrel{.}{I}}_{\mathrm{dC}}={\stackrel{.}{I}}_C-{\stackrel{.}{I}}_0$

In above formula for transformer Y side participates in A phase current, B phase current, the C phase current of differential current computing; for the TA secondary current of access transformer Y side A phase, B phase, C phase, wherein, ${\stackrel{.}{I}}_0=({\stackrel{.}{I}}_A+{\stackrel{.}{I}}_B+{\stackrel{.}{I}}_C)/3;$

(3) in transformer d side, phase transition is carried out by following formula:

${\stackrel{.}{I}}_{\mathrm{da}}=({\stackrel{.}{I}}_c-{\stackrel{.}{I}}_a)/\sqrt{3}$

${\stackrel{.}{I}}_{\mathrm{db}}=({\stackrel{.}{I}}_a-{\stackrel{.}{I}}_b)/\sqrt{3}$

${\stackrel{.}{I}}_{\mathrm{dc}}=({\stackrel{.}{I}}_b-{\stackrel{.}{I}}_c)/\sqrt{3}$

In above formula for a phase after phase compensation, b phase, c phase current are carried out in transformer d side; for the TA secondary current of access transformer d side a phase, b phase, c phase;

(4) by above-mentioned phase transition, make the transformer d side current phase of YNd11 wiring consistent with Y side current phase.

2. YNd5 transformer longitudinal linked differential protection d side current phase compensation method as claimed in claim 1, is characterized in that, the model of described high voltage side of transformer, low-pressure side TA is LJZ series.

3. YNd5 transformer longitudinal linked differential protection d side current phase compensation method as claimed in claim 1, is characterized in that, the model of described high voltage side of transformer, low-pressure side TA is LCZ series.

4. YNd5 transformer longitudinal linked differential protection d side current phase compensation method as claimed in claim 1, is characterized in that, the model of described high voltage side of transformer, low-pressure side TA is LGBJ series.

5. YNd5 transformer longitudinal linked differential protection d side current phase compensation method as claimed in claim 1, is characterized in that, the model of described high voltage side of transformer, low-pressure side TA is LZ2B9 series.