CN101661090A

CN101661090A - Through-flow tester of neutral point current transformer of transformer

Info

Publication number: CN101661090A
Application number: CN200910172241A
Authority: CN
Inventors: 郑新才; 吴建辉; 李明; 张凯
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: 2010-03-03

Abstract

The invention provides a through-flow tester of a neutral point current transformer of a transformer. The tester is provided with four wiring terminals S1, S2, T1 and T2, two alternating current (AC)ammeters A1 and A2 and an alternating current (AC) air switch inside, and is provided with two test lines L1 and L2 and a clip-on current transformer outside. The wiring terminals S1 and S2 are primary output terminals and can output 220V alternating current (AC) voltage. The wiring terminals T1 and T2 are secondary output terminals. The test lines L1 and L2 are primary test lines. The wiring terminals T1 and T2 are connected with the clip-on current transformer by test lines K1 and K2. The tester of the invention can detect the transformation ratio of the neutral point TA of the transformer,avoid mistakenly accessing other transformation ratios of the neutral point TA of the transformer during wiring, thoroughly detect corresponding secondary current loop of the neutral point TA of the transformer, ensure correct running of the transformer, shorten the through-flow time of the neutral point TA of the transformer, improve the running reliability of the transformer and guarantee the stable running of the power systems.

Description

Transformer neutral point current transformer through-flow tester

Technical field

The present invention relates to a kind of transformer neutral point current transformer through-flow 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 (hereinafter to be referred as transformer neutral point TA) is installed between bushing shell for transformer and the transformer neutral point earthing isolator.Be that transformer neutral point TA upper end links to each other with bushing shell for transformer in transformer inside, the lower end links to each other with the transformer neutral point earthing isolator.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), and wherein the ratio of primary current and secondary current is called the no-load voltage ratio of current transformer.

Transformer neutral point TA occupies important effect in tranformer protection, in case there is mistake in its corresponding electric current secondary loop, will cause the irregular operating of transformer.The through-flow test of so-called current transformer is exactly that Current Transformer up-flow instrument feeds big electric current in a winding of current transformer, check its corresponding secondary current current in loop then, not only can check the no-load voltage ratio of current transformer, and can check whether its secondary circuit wiring is correct.The through-flow test of conventional current mutual inductor is that Current Transformer up-flow instrument is connected on the two ends of current transformer through-flow the time, checks its corresponding electric current secondary loop.But transformer neutral point TA is installed between bushing shell for transformer and the transformer neutral point earthing isolator, and its upper end links to each other with bushing shell for transformer in transformer inside, and through-flow test is carried out at the two ends that can't Current Transformer up-flow instrument be connected on current transformer.Terminate on the sleeve pipe of transformer as if one of Current Transformer up-flow instrument in addition, the other end is connected on the transformer neutral point earthing isolator and does through-flow test, though this kind test method is the two ends that current transformer up-flow instrument 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, the up-flow instrument can't pass through electric current by between, so also can't do through-flow test.Therefore how be the most important thing of all work at the put into operation line transformer neutral point TA through-flow test that advances of transformer.

Present stage, how there is the blank of equipment and technology in the through-flow test that transformer neutral point TA is done science always, there is not special test apparatus, when testing as if the no-load voltage ratio that need be transformer neutral point TA generally speaking, all be that Current Transformer up-flow instrument was done through-flow test to transformer neutral point TA separately on the ground after depressor neutral point TA was dismantled from transformer.This in fact way is very unilateral, and it just checks the no-load voltage ratio of transformer neutral point TA itself, its corresponding electric current secondary loop is not checked, in case the electric current secondary loop existing problems will cause the harm of following three aspects.(1) can't check its secondary circuit comprehensively.Can not guarantee that transformer normally moves; (2) can not check whether its secondary circuit wiring is correct, the preceding pre-control of the accident of can't accomplishing; (3) waste a large amount of human and material resources, time.If can be according to some correlation properties of transformer, inventing a kind of test apparatus, to do the through-flow test of transformer neutral point TA be a very important problem.

Summary of the invention

For fear of above various shortcoming, the present invention proposes the through-flow test instrument of a kind of transformer neutral point TA and corresponding test method, this test instrument is simple to operate, can overhaul no-load voltage ratio and the corresponding electric current secondary loop of transformer neutral point TA, accomplishes the pre-control that accident is preceding; Guaranteed the safe and stable operation of electrical network.

Solving the technical scheme that problem of the present invention adopted is: there are four connection terminals this test instrument inside, be S1 terminal, S2 terminal, T1 terminal, T2 terminal, two alternating current ammeter A1, A2, an interchange air switch DK, there are two test wires the outside, i.e. L1, L2 test wire and a pincerlike current sensor; Wherein S1 terminal, S2 terminal are primary output terminals, can export the 220V alternating voltage; T1 terminal, T2 terminal are secondary output terminals, and L1, L2 test wire are the single test line; A terminal at inner S1 terminal of test instrument and alternating current ammeter A1 links to each other, and another terminal of alternating current ammeter A1 links to each other with the L1 test wire; The S2 terminal links to each other with a terminal that exchanges air switch DK, and another terminal that exchanges air switch DK links to each other with the L2 test wire; The terminal of T1 terminal and alternating current ammeter A2 links to each other, the T1 terminal also links to each other with the K1 test wire of pincerlike current sensor simultaneously, the another one terminal of T2 terminal and alternating current ammeter A2 links to each other, and the T2 terminal also links to each other with the K2 test wire of pincerlike current sensor simultaneously.

The through-flow test method of transformer neutral point TA is: at first with step down side three-phase cover tube short circuit ground connection, the L1 test wire is connected on the connection terminal of transformer high-voltage side A phase sleeve pipe, and the L2 test wire is connected between transformer neutral point TA and the transformation neutral ground disconnector; Be stuck in pincerlike current sensor on the secondary current loop of transformer neutral point TA, close then and exchange air switch DK, the numerical value of reometer A1 is exactly the no-load voltage ratio of transformer neutral point TA divided by the numerical value of reometer A2 at this moment, and then whether check its electric current of measuring no-load voltage ratio and secondary circuit according to the actual no-load voltage ratio of transformer neutral point TA correct.

Good effect of the present invention is: can check the no-load voltage ratio of transformer neutral point TA, mistake inserts other no-load voltage ratio of transformer neutral point TA when avoiding wiring; Can overhaul the corresponding electric current secondary loop of transformer neutral point TA, guarantee the transformer true(-)running; Shorten the through-flow time of transformer neutral point TA, improved the transformer reliability of operation, ensured the stable operation of electric system.

Description of drawings

Fig. 1 is a test principle synoptic diagram of the present invention.

Embodiment

As shown in drawings, one of this test instrument 1 inner S1 terminal 2 and AC power 22 extremely links to each other, and another of S2 terminal 5 and AC power 22 extremely links to each other, and can export the alternating voltage of 220V between the two; The two ends of reometer A1 3 link to each other with L1 test wire 4 with S1 terminal 2 respectively; The two ends that exchange air switch DK 19 link to each other with L2 test wire 6 with S2 terminal 5 respectively; The two ends of reometer A28 link to each other with T2 terminal 10 with T1 terminal 7 respectively, and the K1 test wire 9 of T1 terminal 7 and pincerlike current sensor 20 links to each other simultaneously, and the K2 test wire 11 of T2 terminal 10 and pincerlike current sensor 20 links to each other.

Its test method is:

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

(2) one of L1 test wire 4 is terminated on the transformer high-voltage side A phase sleeve pipe 12, one of L2 test wire 6 is terminated between transformer neutral point TA 13 and the transformation neutral ground disconnector 14, and disconnection neutral ground disconnector 14, terminate on the neutral ground disconnector 14 on the neutral point TA 13, terminate on the grounding net of transformer substation 15 down;

(3) pincerlike current sensor 20 is stuck on the secondary current loop 21 of transformer neutral point TA;

(4) close and exchange air switch DK 19;

(5) read the numerical value of alternating current ammeter A1 3 and alternating current ammeter A2 8;

(6) no-load voltage ratio of transformer neutral point TA 13 numerical value that equals alternating current ammeter A1 3 is removed the numerical value of alternating current ammeter A2 8;

(1) if close with transformer neutral point TA 13 actual no-load voltage ratios, thinks that then its no-load voltage ratio and its corresponding secondary circuit wiring are correct according to the no-load voltage ratio of calculating in (6).

Claims

1, a kind of transformer neutral point current transformer through-flow tester, it is characterized in that: there are four connection terminals this test instrument inside, be S1 terminal (2), S2 terminal (5), T1 terminal (7), T2 terminal (10), two alternating current ammeter A1, A2 (3,8), an interchange air switch DK (19), there are two test wire L1, L2 (4,6) and a pincerlike current sensor (20) in the outside; Wherein S1 terminal (2), S2 terminal (5) are primary output terminals, can export the 220V alternating voltage; T1 terminal (7), T2 terminal (10) are secondary output terminals, and L1 test wire (4), L2 test wire (6) are the single test line; A terminal at inner S1 terminal (2) of test instrument and alternating current ammeter A1 (3) links to each other, and another terminal of alternating current ammeter A1 (3) links to each other with L1 test wire (4); S2 terminal (5) links to each other with a terminal that exchanges air switch DK (19), and another terminal that exchanges air switch DK (19) links to each other with L2 test wire (6); The terminal of T1 terminal (7) and alternating current ammeter A2 (8) links to each other, another terminal of alternating current ammeter A2 (8) is connected on the K1 test wire (9) of pincerlike current sensor (20), and T2 terminal (10) is connected on the K2 test wire (11) of pincerlike current sensor (20).

2, transformer neutral point current transformer through-flow tester according to claim 1, its test method is: at first with step down side three-phase cover tube short circuit ground connection, L1 test wire (4) is connected on the connection terminal of transformer high-voltage side A phase sleeve pipe, and L2 test wire (6) is connected between transformer neutral point TA (13) and the transformation neutral ground disconnector (14); Be stuck in pincerlike current sensor (20) on the secondary current loop (21) of transformer neutral point TA, close then and exchange air switch DK (19), the numerical value of alternating current ammeter A1 this moment (3) is exactly the no-load voltage ratio of transformer neutral point TA (13) divided by the numerical value of alternating current ammeter A2 (8), and then whether check its electric current of measuring no-load voltage ratio and its secondary current loop (21) according to the actual no-load voltage ratio of transformer neutral point TA (13) correct.