CN101692115A

CN101692115A - Polarity tester for current transformer at transformer neutral point

Info

Publication number: CN101692115A
Application number: CN200910172240A
Authority: CN
Inventors: 郑新才; 吴建辉; 李明; 高世伟
Original assignee: HUNAN ELECTRIC POWER COMPANY SHANGQIU POWER SUPPLY Co
Current assignee: HUNAN ELECTRIC POWER COMPANY SHANGQIU POWER SUPPLY Co
Priority date: 2009-09-23
Filing date: 2009-09-23
Publication date: 2010-04-07

Abstract

The invention relates to a polarity tester for a current transformer at a transformer neutral point. The tester is internally provided with four terminals, a pointer type DC current milliampere meter A and a test button, and is externally provided with four test wires; a forward 220V DC voltage can be output between a positive primary terminal and a negative primary output terminal; the other two terminals are secondary output terminals; the internal positive primary terminal of the tester is connected with a primary test wires; the negative primary output terminal is connected with one terminal of the test button, and the other terminal of the test button is connected with the other primary test wire; and the two secondary output terminals are connected with an anode and a cathode of the pointer type DC ammeter respectively and are connected with the two secondary test wires at the same time. The tester can accurately check the polarity of the TA secondary winding of the transformer neutral point, avoids incorrect access during connection, improves the operation reliability of a transformer, and ensures the stable operation of a power system.

Description

Transformer neutral point current transformer polarity tester

Technical field

The present invention relates to a kind of transformer neutral point current transformer polarity test instrument, belong to relay protection of power system and automatic safety device check field.

Background technology

Transformer station is the power supply hinge of electric system, and it is powered to the user by the transformer in the transformer station.Transformer neutral point current transformer (being called for short transformer neutral point TA) also is a kind of current transformer in fact, and the current transformer effect is to convert big electric current (primary current) to little electric current (secondary current).Transformer neutral point TA is installed between bushing shell for transformer and the transformer neutral point earthing isolator.Be transformer neutral point TA upper end (polar end) transformer inside and bushing shell for transformer non-polar end link to each other, lower end (non-polar end) links to each other with the transformer neutral point earthing isolator.Transformer neutral point TA occupies important effect in tranformer protection, in case there is mistake in its polarity wiring, will cause the irregular operating of transformer.The polarity of so-called current transformer (hereinafter to be referred as TA) be meant it winding and Secondary Winding between the relation of direction of current, current transformer winding head end L1 is a polar end according to the rules, tail end L2 is a non-polar end, the head end K1 of Secondary Winding is a polar end, tail end K2 is nonpolar, wherein L1 and K1 are end of the same name, and L2 and K2 are end of the same name.If Secondary Winding polarity wiring error; to cause the protection equipment for transformer false judgment; on the one hand when transformer generation earth fault; the failure transformer tripping operation is stopped transport; other does not have the transformer tripping operation of fault to stop transport in the transformer station with causing, and causes the damage of failure transformer on the other hand yet.The polarity test of conventional current mutual inductor is to be added in polar end L1 of current transformer with 9V dc-battery positive pole, 9V dc-battery negative pole is added in non-polar end L2 of current transformer, be connected on the polar end K1 of the secondary winding of current transformer with the positive pole of dc milliammeter, the negative pole of dc milliammeter is connected on the non-property end K2 of the secondary winding of current transformer.When dc milliammeter pointer forward rotation thinks that then secondary polarity is correct, dc milliammeter pointer backward rotation is then thought the secondary incorrect polarity, but transformer neutral point TA is installed between bushing shell for transformer and the transformer neutral point earthing isolator, its polar end links to each other with bushing shell for transformer in transformer inside, can't carry out polarity test with the two ends that the 9V dc-battery is connected on current transformer.In addition if be connected on the sleeve pipe of transformer with the 9V anode, negative pole is connected on the transformer neutral point earthing isolator and does polarity test, though this kind test method is the two ends that the 9V dc-battery are connected on depressor neutral point TA on principle, but owing between bushing shell for transformer and the transformer neutral point earthing isolator very large impedance is arranged, 9V dc-battery between does not have electric current to generate, so can't do the polarity test test yet.Therefore how be the most important thing of all work at the put into operation line transformer neutral point TA property testing that advances of transformer.

Present stage, how there is the blank of technology in the property testing test that transformer neutral point TA is done science always, producer is before transformer neutral point TA is installed in transformer, separately transformer neutral point TA is done the polarity test test on the ground, the transformer assembling finishes to be transported to and no longer does any test before transformer station puts into operation.This in fact way is very unilateral, it is equivalent to not do the polarity check test again after the transformer secondary wiring, in case secondary polarity existing problems can cause the harm of following two aspects equally: (1) is when transformer generation earth fault, the failure transformer tripping operation is stopped transport, other does not have the transformer tripping operation of fault to stop transport to make transformer station on the contrary, causes the power failure expanded range; (2) when transformer generation earth fault, the failure transformer tripping operation is stopped transport, cause the damage of failure transformer.If can be before transformer puts into operation, according to some correlation properties of transformer, the polarity test of being transformer neutral point TA with the method that applies the 220V DC voltage be a kind of test method of novel science.

Summary of the invention

For fear of above various shortcoming, the present invention proposes the polarity test instrument of a kind of transformer neutral point TA and corresponding test method, this tester is simple to operate, can overhaul transformer neutral point TA polarity, accomplishes the pre-control that accident is preceding; Can guarantee the safe and stable operation of electrical network.

Solving the technical scheme that problem of the present invention adopted is: invent a kind of transformer neutral point current transformer polarity tester, there are four connection terminals this tester inside, be S1 terminal, S2 terminal, T1 terminal, T2 terminal, a pointer direct current electric current milliammeter A, a test button, there are four test wires the outside, and wherein L1, L2 test wire are the single test line, and K1, K2 test wire are the second trial line; The S1 terminal is the negative pole primary output terminals for anodal terminal, a S2 terminal, can export forward 220V DC voltage between the two; T1, T2 terminal are secondary output terminals; Link to each other with single test line L1 test wire at the inner S1 terminal of tester; The S2 terminal links to each other with a terminal of test button, and another terminal of test button links to each other with single test line L2 test wire; The T1 terminal links to each other with the positive terminal of the A of pointer direct current reometer, the T1 terminal also links to each other with second trial line K1 test wire simultaneously, the T2 terminal links to each other with the negative terminal of the A of pointer direct current reometer, and the T2 terminal links to each other with second trial line K2 test wire simultaneously.

The polarity test method of transformer neutral point TA is: at first the step down side three-phase is overlapped effective thick copper lines short circuit ground connection, disconnect the transformer neutral point earthing isolator then, single test line L1 test wire is connected on the polar end of arbitrary phase sleeve pipe of transformer high-voltage side A, B, C three-phase sleeve pipe, single test line L2 test wire is connected on the non-polar end of transformer neutral point TA; Second trial line K1 test wire is connected on the polar end of the secondary winding of transformer neutral point current transformer, second trial line K2 test wire is connected on the non-polar end of the secondary winding of transformer neutral point current transformer; Moment applies the DC voltage of forward 220V; Cross primary current with transient flow this moment in transformer neutral point TA, induce secondary current at its secondary side also moment simultaneously.If dc milliammeter pointer forward rotation thinks that then secondary polarity is correct, dc milliammeter pointer backward rotation is then thought the secondary incorrect polarity.

Good effect of the present invention is: can accurately check the polarity of transformer neutral point TA Secondary Winding, mistake inserts when avoiding wiring; Improve the transformer reliability of operation, ensured the stable operation of electric system.

Description of drawings

Accompanying drawing is tester of the present invention and test philosophy synoptic diagram.

Embodiment

Accompanying drawing is a kind of specific embodiment of the present invention, and the positive pole of test instrument 1 inner S1 terminal 2 and direct supply 20 links to each other, and S2 terminal 4 links to each other with the negative pole of direct supply 20, can export the DC voltage of forward 220V between the two, and S1 terminal 2 links to each other with L1 test wire 3; The two ends of test button 5 link to each other with L2 test wire 11 with S2 terminal 4 respectively; The positive pole of reometer A7 links to each other with T1 terminal 6, and the negative pole of reometer A7 links to each other with T2 terminal 8, and T1 terminal 6 links to each other with K1 test wire 9; T2 terminal 8 links to each other with K2 test wire 10.

Concrete method of testing is:

(1) step down side A phase sleeve pipe 16, B phase sleeve pipe 17, C phase sleeve pipe 18 three-phases are attempted by on the grounded screen of transformer station with the thick copper lines short circuit.

(2) one of single test line L1 test wire 3 is terminated on the transformer A phase sleeve pipe polar end 12, one of single test line L2 test wire 11 is terminated at the non-polar end of transformer neutral point TA13, and disconnection transformer neutral point earthing isolator 14, terminate on the transformer neutral point earthing isolator 14 on the transformer neutral point TA13, terminate on the grounding net of transformer substation 15 down.

(3) second trial line K1 test wire 9 is connected on the polar end of depressor neutral point TA Secondary Winding 19, second trial line K2 test wire 10 is connected on the non-polar end of depressor neutral point TA Secondary Winding 19.

(4) press test button 5 back and unclamping in short-term.

(5) if dc milliammeter pointer forward rotation thinks that then secondary polarity is correct, dc milliammeter pointer backward rotation is then thought the secondary incorrect polarity.

Claims

1. transformer neutral point current transformer polarity tester, it is characterized in that: there are four connection terminals this tester inside, be S1 terminal (2), S2 terminal (4), T1 terminal (6), T2 terminal (8), a pointer direct current electric current milliammeter A (7), a test button (5), outside have four test wire L1, L2, K1, K2 (3,11,9,10); S1 terminal (2) is that an anodal terminal, S2 terminal (4) are the negative pole primary output terminals, can export forward 220V DC voltage between the two; T1, T2 terminal (6,8) are secondary output terminals; S1 terminal (2) links to each other with single test line L1 test wire (3); S2 terminal (4) links to each other with a terminal of test button (5), and another terminal of test button (5) links to each other with single test line L2 test wire (11); T1 terminal (6) links to each other with the positive terminal of the A (7) of pointer direct current reometer, T1 terminal (6) also links to each other with second trial line K1 test wire (9) simultaneously, T2 terminal (8) links to each other with the negative terminal of the A (7) of pointer direct current reometer, and T2 terminal (8) also links to each other with second trial line K2 test wire (10) simultaneously.

2. transformer neutral point current transformer polarity tester according to claim 1, its method of testing is: at first step down side three-phase sleeve pipe (16,17,18) is used thick copper lines short circuit ground connection, disconnect transformer neutral point earthing isolator (14) then, L1 test wire (3) is connected on the polar end (12) of arbitrary phase sleeve pipe of transformer high-voltage side A, B, C three-phase sleeve pipe, L2 test wire (11) is connected on the non-polar end of transformer neutral point TA (13); K1 test wire (9) is connected on the polar end of the secondary winding (19) of transformer neutral point TA (13), K2 test wire (10) is connected on the non-polar end of the secondary winding (19) of transformer neutral point TA (13); Moment applies the DC voltage of forward 220V; Cross primary current with transient flow this moment in transformer neutral point TA (13), induce secondary current at its secondary side also moment simultaneously.