CN104198875A - Inspection method for transformer differential protection wiring - Google Patents

Abstract

The invention discloses an inspection method for transformer differential protection wiring. The method includes setting a bus side of a high voltage side of the transformer as a main power side and a positive electrode and setting a transformer side as a main power side and a positive electrode for a medium voltage side and the low voltage side when the polarity of a current transformer is determined; using I`a1, I`b1 and I`C1 as loop phase current of the current transformer and using Ia1, Ib1 and IC1 as loop line current of the current transformer when the connection mode of the current transformer of the high voltage side is used; using I`a2, I`b2 and I`C2 as loop phase current of the current transformer of the medium voltage side and using Ia2, Ib2 and IC2 as loop line current of the current transformer of the medium voltage side when the connection mode of the current transformer of the medium voltage side is used; using I`a3, I`b3 and I`C3 as loop phase current of the current transformer of the low voltage side and using Ia3, Ib3 and IC3 as loop line current of the current transformer of the low voltage side when the connection mode of the current transformer of the low voltage side is used.

Description

A kind of inspection method for transformer differential protection wiring

Technical field

The present invention relates to field transformer, relate in particular to a kind of inspection method for transformer differential protection wiring.

Background technology

In industrial electric construction, transformer differential protection wiring check method is a difficult problem of puzzlement transformer differential protection always.In traditional construction operation, be first the polarity of determining current transformer first and second side.Secondly; according to schematic diagram, carry out circuit check and correction and wiring, then test the correctness of determining wiring and relay protection, can not bring into play the effect of differential protection; usually the malfunction because of differential protection can not normally move transformer, causes great casualties and economic loss.

Summary of the invention

The invention provides a kind of inspection method for transformer differential protection wiring, the invention solves existing transformer differential protection wiring constructing technology problem, described below:

An inspection method for transformer differential protection wiring, said method comprising the steps of:

At definite current transformer polarity chron, transformer high-voltage side-looking bus bar side is primary power side, gets bus bar side for just, in, low-pressure side take transformer side as primary power side, all gets transformer side for just;

During high voltage side current mutual inductor connected mode: I`a1, I`b1, I`C1 are current transformer loop phase current, Ia1, Ib1, IC1 are current transformer loop line current;

During medium voltage side current transformer connected mode: I`a2, I`b2, I`c2 are medium voltage side current transformer loop phase current; Ia2, Ib2, Ic2 are medium voltage side current transformer loop line current;

During low-pressure side current transformer connected mode: I`a3, I`b3, I`c3 are low-pressure side current transformer loop phase current, Ia3, Ib3, Ic3 are low-pressure side current transformer loop line current.

The beneficial effect of technical scheme provided by the invention is: in practical application; the wiring that just can guarantee according to the method described above differential protection current return is correct; the invention solves existing transformer differential protection wiring constructing technology problem, avoided great casualties and economic loss.

Accompanying drawing explanation

Fig. 1 is that power taking source is timing differential protection current transformer connection figure;

Fig. 2 is high-pressure side differential protection loop current vector figure;

Fig. 3 is medium voltage side differential protection loop current vector figure;

Fig. 4 is low-pressure side differential protection loop current vector figure.

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below embodiment of the present invention is described further in detail.

One, reference power source side Differential Protection Connection method

At definite current transformer polarity chron, three sides are all got primary power side for just.If transformer high-voltage side-looking bus bar side is primary power side, get bus bar side for just, in, low-pressure side take transformer side as primary power side, all get transformer side for just, and then according to above supposition, determine corresponding secondary side polarity.So, differential protection current transformer loop just should connect (equal Y/Y/ Δ one 12 one 11 wiring of wiring group of the three-winding transformer of discussion) in the following manner:

Fig. 1 has drawn and ought three sides all get the differential protection current transformer loop elementary diagram that primary power side is timing.Direction in figure shown in arrow is the positive dirction of electric current.The direction that current transformer primary side current is represented, is transformer load sense of current under normal operation.In addition, in figure, be marked with the positive ends that " ☆ " person is current transformer primary side, be marked with " * " person for the positive ends of Current Transformer Secondary side.For ease of discussing, high, medium and low three sides are introduced respectively:

1, high voltage side current mutual inductor connected mode

As can be seen from Figure 1, the order of connection of high-pressure side differential protection current transformer loop is a+ → b-→ b+ → c-→ c+ → a-, and is positive polarity outlet.For ease of memory, say above Current Transformer Secondary side connected mode, corresponding to the wiring of transformer high-voltage coil, be equivalent to Y/ Δ one 11 wiring groups.As the reverse value-IAl that gets the A phase current in high-pressure side is reference vector, and according to the current direction shown in Fig. 1, can draw high-pressure side differential protection loop current vector figure as shown in Figure 2.Wherein: I`a1, I`b1, I`C1 are current transformer loop phase current, Ia1, Ib1, IC1 are current transformer loop line current.

2, medium voltage side current transformer connected mode

The wiring of seeing Fig. 1 medium voltage side differential protection current transformer loop is known, and its order of connection is a-→ b+ → b-→ c+ → c-→ a+, and is negative polarity outlet.Above Current Transformer Secondary side connected mode, corresponding to the wiring of transformer high-voltage coil, is equivalent to one 5 wiring of Y/ Δ.

If get equally the reverse value-IA1 of the A root electric current in high-pressure side and be reference vector (below all with), and according to the current direction shown in Fig. 1, can draw medium voltage side differential protection loop current vector figure as shown in Figure 3.Comparison diagram 3 and Fig. 2 are known, now medium voltage side current transformer loop secondary side line current (being differential circuit electric current, as follows) and high voltage side current transformer circuit secondary side line current, and both are just in time reverse.Concerning hypothesis primary current is the situation of the load current under normal operation, there is the result that differential circuit electric current offsets in this, the wiring that above differential protection current transformer loop is described is right-on.

Wherein.I`a2, I`b2, I`c2 are medium voltage side current transformer loop phase current; Ia2, Ib2, Ic2 are medium voltage side current transformer loop line current.

3, low-pressure side current transformer connected mode

From Fig. 1, be also shown in, the connected mode of low-pressure side differential protection current transformer loop is the star-star connection of negative polarity outlet, therefore corresponding to the wiring of transformer high-voltage coil, be equivalent to Y/Y-6 wiring.Fig. 4 has drawn the current vector figure of above wiring, visible, and it is under normal operation, and differential protection loop low-pressure side electric current and high voltage side current are also reverse.

Wherein: I`a3, I`b3, I`c3 are low-pressure side current transformer loop phase current, Ia3, Ib3, Ic3 are low-pressure side current transformer loop line current.

Introduced a kind of construction method of differential protection current transformer loop wiring above, therefore, as long as carry out wiring by above-described principle, just can also guarantee that the wiring of differential protection current return is correct.

The present invention's embodiment at the trial:

1, utilize comprehensive relay-protection tester to test, detection system current data and phase place correctness are measured the electric current in differential winding simultaneously.

2, large current analog system test is further measured current data and phase place correctness, measures the size of current of differential winding simultaneously, and result should be correct.

3, before power transmission, take relay output brace apart, make differential protection exit protection system and measure, further measure the size of current data and difference current, result should be correct.The brace that connects relay protection output, allows differential protection put into operation.Thereby show that above-mentioned wiring is correct.

It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.

The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (1)

1. for an inspection method for transformer differential protection wiring, it is characterized in that, said method comprising the steps of:

At definite current transformer polarity chron, transformer high-voltage side-looking bus bar side is primary power side, gets bus bar side for just, in, low-pressure side take transformer side as primary power side, all gets transformer side for just;

During high voltage side current mutual inductor connected mode: I`a1, I`b1, I`C1 are current transformer loop phase current, Ia1, Ib1, IC1 are current transformer loop line current;

During medium voltage side current transformer connected mode: I`a2, I`b2, I`c2 are medium voltage side current transformer loop phase current; Ia2, Ib2, Ic2 are medium voltage side current transformer loop line current;

During low-pressure side current transformer connected mode: I`a3, I`b3, I`c3 are low-pressure side current transformer loop phase current, Ia3, Ib3, Ic3 are low-pressure side current transformer loop line current.