CN1747272A

CN1747272A - Protection of unbalanced TCR circuit

Info

Publication number: CN1747272A
Application number: CN 200510093661
Authority: CN
Inventors: 杨建宁; 王俭; 祝瑾
Original assignee: Beijing Aritime Intelligent Control Co Ltd
Current assignee: Beijing Aritime Intelligent Control Co Ltd
Priority date: 2005-09-01
Filing date: 2005-09-01
Publication date: 2006-03-15
Anticipated expiration: 2025-09-01
Also published as: CN100495849C

Abstract

The method uses ratio of three phase reactive power to three phase active power to judge three phase balance state of system. TCR current is taken from phase current out of trigon.

Description

A kind of imbalance protecting method that is applied to the TCR circuit

Technical field

The present invention relates to a kind of imbalance protecting method of a kind of thyristor-controlled reactor (TCR) circuit, relate to the imbalance protecting method of used TCR circuit in a kind of medium voltage network improvement especially.

Background technology

In the technical scheme that medium voltage network is administered, using maximum is the TCR circuit, and this circuit structure form is a delta connection.For guaranteeing the TCR reliably working; need perfect defencive function; wherein there is an important protection monitoring project to be: when balanced load is worked; detect the non-equilibrium state of TCR; the generation of this non-equilibrium state; may be by losing trigger impulse, the thyristor valve string high-voltage breakdown, reactor has reasons such as local damage to cause.In case non-equilibrium state occurred, then TCR has been in irregular working, needs shutdown inspection.

For this situation, at present domestic and international each major company all adopts three current signals in the triangle of taking from the TCR circuit when detecting the non-equilibrium state of TCR, judge the non-equilibrium state of the amplitude of three-phase current, use the difference of current amplitude to judge degree of unbalance.The circuit diagram of conventional TCR and the acquisition mode of electric current as shown in Figure 1, a-b, c-d, e-f are respectively the sampled point at instrument transformer TA11, TA12 in the three phase mains, TA13 two ends among the figure.And take as shown in Figure 1 acquisition mode, according to the result of AD sampling, judge directly whether there is following difficulty in balance to three-phase current: the current distortion of (1) TCR circuit in the trigonum is big, contain a large amount of characteristic harmonics, amplitude with 3 subharmonic is a maximum, during electric current AD sampling, sampling error is arranged; (2) under situations such as line voltage three-phase imbalance, reactor foozle, trigger impulse error, the situation of three-phase current unbalance also may appear in system.And above-mentioned problem will cause system protection to calculate the error that occurs, and may cause system misoperation to occur, has reduced the security reliability of system.

Summary of the invention

Purpose of the present invention promptly is the unbalanced guard method of a kind of safe and reliable TCR circuit that proposes at above-mentioned problems of the prior art.

Purpose of the present invention adopts following technical proposals to realize:

A kind of imbalance protecting method that is applied to the TCR circuit utilizes the ratio of three phase reactive power, comparison reactive power and active power, judges the three-phase equilibrium state of system.

The TCR electric current is taken from the outer a1-b1 of triangle, c1-d1, the phase current at e1-f1 place.

The present invention has following remarkable advantage:

(1) unbalance protection accurately, reliably system do not occur and fails to report, the wrong report error message;

(2) simple in structure, in using, engineering implements simple, easy row.

Description of drawings

Fig. 1 is the circuit diagram of the TCR of routine.

Fig. 2 is the circuit diagram of TCR of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments the present invention is further introduced, but not as a limitation of the invention.

The load of TCR circuit is inductive, electric current lagging voltage 90 degree under the perfect condition.During poised state work, thyristor is regulated the size of reactor current, and electric current is the inductance current based on lagging voltage, has a spot of resistive electric current in the circuit, and the performance number of measuring is based on reactive power, and the active power value is very little.During non-equilibrium state work, three-phase current not only has the uneven difference of amplitude, and the angle between electric current and voltage changes, and active power calculating value obviously increases, reactive power calculating value reduces, and the ratio that calculates reactive power and active power obviously reduces.

Thereby; the imbalance protecting method of a kind of TCR of being applied to circuit that the present invention proposes promptly is at above-mentioned feature; by comparing the ratio of three phase reactive power, comparison reactive power and active power, judge the three-phase equilibrium state of system, more increased the reliability of system.The benefit of this method is, not only considers the amplitude size of electric current, considered that also the argument of electric current changes, and is the notion of plural number.

With reference to figure 2, when utilizing said method to calculate, the TCR electric current is taken from the outer a1-b1 of triangle, c1-d1, and the phase current at e1-f1 place, when system's operate as normal, three-phase equilibrium, third-harmonic component is very little in the phase current.When three-phase imbalance took place, outer 3 subharmonic of triangle are little than in the triangle also.Electric current is taken from triangle and is convenient to filtering sampling outward, becomes desirable sine wave easily, and it is more accurate to calculate.

Adopt above-mentioned hookup and computational methods, as follows by the test data of hookup:

The TCR operating voltage is 18V, test TCR loop is when different test angle, the TCR controller is gathered by A/D, calculates three phases active power and reactive power perunit value, writes down shown in following table 1 and table 2 according to normal equilibrium attitude and two kinds of situations of undesired uneven attitude:

Table 1:

Trigger angle	Equilibrium state					On average idle/average meritorious
	Equilibrium state							U (perunit value)	V (perunit value)	W (perunit value)	On average
	103	Reactive power	1066	1068	1093			U (perunit value)	V (perunit value)	W (perunit value)	On average	1075.67	4.15
Active power		Reactive power	1066	1068	1093	291	231	256	259.33			1075.67	4.15
Active power		113	Reactive power	910	825	291	231	256	259.33		873	869.33	4.41
Active power	236		Reactive power	910	825	171	184	197.00			873	869.33	4.41
Active power	236		123	Reactive power	703	171	184	197.00		569	652	641.33	4.74
Active power	170	108		Reactive power	703	128	135.33			569	652	641.33	4.74
Active power	170	108		133	Reactive power	128	135.33		488	364	436	429.33	5.13
Active power	121	58	72		Reactive power	83.67			488	364	436	429.33	5.13
Active power	121	58	72		143	83.67		Reactive power	285	165	258	236.00	5.28
Active power	77	17	40	44.67				Reactive power	285	165	258	236.00	5.28

Table 2:

Trigger angle	Uneven attitude (lacking 1 phase optical fiber)				On average	On average idle/average meritorious
	Uneven attitude (lacking 1 phase optical fiber)							U (perunit value)	V (perunit value)	W (perunit value)
	103	Reactive power	591	376				U (perunit value)	V (perunit value)	W (perunit value)	1062	676.33	2.71
Active power		Reactive power	591	376	180	234	336	250.00			1062	676.33
Active power		113	Reactive power	486	180	234	336	250.00	316	811	537.67	2.82
Active power	143		Reactive power	486	166	264	191.00		316	811	537.67
Active power	143		123	Reactive power	166	264	191.00	382	227	599	402.67		2.78
Active power	126	108		Reactive power	200	144.67		382	227	599	402.67
Active power	126	108		133	200	144.67	Reactive power	292	141	401	278.00	3.04
Active power	86	60	128		91.33		Reactive power	292	141	401	278.00
Active power	86	60	128		91.33	143	Reactive power	188	49	236	157.67		3.50
Active power	56	15	64	45.00			Reactive power	188	49	236	157.67

Can draw from test data, when being in equilibrium state, the ratio of reactive power and active power＞4, during the imbalance attitude, the ratio of reactive power and active power obviously reduces, and is 2～3, can judge the uneven attitude of TCR from the ratio of reactive power and active power.

Specific embodiment of the present invention has been made detailed explanation to content of the present invention, for persons skilled in the art, the any conspicuous change that it is done without departing from the premise in the spirit of the present invention, all constitute to infringement of patent right of the present invention, with corresponding legal responsibilities.

Claims

1, a kind of imbalance protecting method that is applied to the TCR circuit is characterized in that:

Utilize the ratio of three phase reactive power, comparison reactive power and active power, judge the three-phase equilibrium state of system.

2. a kind of imbalance protecting method that is applied to the TCR circuit as claimed in claim 1 is characterized in that:

The TCR electric current is taken from the outer phase current of triangle.