SU1494106A1 - Phase regulator for automatic maintenance of capacitive current compensation conditions in cable network with arc extinction reactor - Google Patents

Abstract

This invention relates to electrical engineering, in particular, to devices for automatically compensating for capacitive ground-fault currents. The purpose of the invention is to simplify and increase reliability. The regulator is provided with correction feedback from the output of the relay link 8 to its input, including a multiplier 9 and a low-pass filter 10. At the same relay link 8, the functions of stabilizing the amplitude of the signal from the output of the object 2 and the pulse-width conversion of the detected signal. This sequence of operations leads to the invariance of the control signal from the network parameters, and its linear dependence on the detuning leads to the construction of a meter for the magnitude of the uncompensated reactive current of the earth fault. 1 il.

Description

with

The invention relates to electrical engineering, in particular, to devices for automatically compensating the capacitance of ground fault currents in power supply cable systems with neutral earthing through an arc-suppressing reactor.

The purpose of the invention is to simplify and increase reliability.

The drawing shows the functional diagram of the phase regulator

In the drawing, an artificial asymmetry unit 1, a network 2, an arcing reactor 3, a neutral displacement voltage sensor 4, a reference signal sensor 5, a large-scale converter 6, an adder 7, a relay element 8, a multiplier (multiplier) 9, filters 10 are indicated. , 11 low frequencies, adder 12, reactor control unit 13, detuning indicator 14, setpoint setting unit 15, mode detection unit 16.

The device works as follows.

Let the input signal of the relay link 8 receives the total signal

X (t) tK fe (t) + Y, (1) tr

where m is the transmission coefficient of the scale converter; K - transformation ratio

block 4;

Y is some non-oscillatory. signal from the output of the block Yu,

Then the signal L (t) at the output of the relay link 8 is described by the relation

L (t) Hsign (Y-HnKT. (+ + (F - v

where H is the level of limitation of the link 8

Representing this (pulse-modulated pulse) sequence of rectangular pulses by the Fourier superframe, we obtain the extension of the form

L (t) HFo () HF / Y / mKTpeJcos (li) t-H / + v) +

+ j. (t). (2)

where -vCt) are the residual terms of the Fourier superframe, including the carrier frequencies nW (n 2, 3,.,);

FCY / mKrpeJ

2fllrcsin (); (H)

F (Y / mK, peJ

  arcsin (, (4)

Multiplying the voltage (3) by the multiplier 9 by the reference signal Bsin (+ / a), generated by block 5, and then selecting the non-oscillating component of filter 10, we obtain the second input Y of the adder 7 as

Y 0.5 bHW (D) F, (Y / mK x

X e sind + V - / s), (5)

and the output of the filter 11 after filtering the signal L (t) is converted to the expression

V W, (D) HF (Y / m .. (b)

By choosing the phase of the reference signal, we neutralize the influence of the phase v of the current Q (t) asymmetry so that in formula (5)

0

sin (V -.) sin If, (7)

Since the value of Y in (5) according to (4) does not exceed the given constant, where K, W, (o) is the transmission coefficient of the filter 10, to find Y from expression (5) it is enough to require the fulfillment of the inequality

1 Y / dnK -peJ 2HKFU ():

40

40.3 ...

(eight)

This inequality is provided by choosing the parameters K / t for all possible values of e e (b, c, g).

Indeed, in view of (8), the maximum deviation of P (h) in (5) from the 4/1 G constant does not exceed 5%, since

50

Ff (l) arcsint / G 4 4tr Vl-0.3, 95,

55 Therefore, the fluctuation of the quantity) in (5) can be neglected, and the ratio itself can be rewritten as

Y K sincf, K, 2K, NN1G (9)

Completion of inequality (8) provides, in addition, the linearization of the arcsine in (3), namely

fp (} 2 IT arc sin "1 p. IT. 1. (lO

Substituting (9), (lO) in (6), we obtain at the output of filter 11 a control signal of the final form

V Кф ,, Н X

X 2G to s1p “Y (1pKt, e„)

 (D) H, (B)

fll) lw (io)) / y

 T in 7Shi} T

 W, (D)) -K ° -Y (12)

where K 4bHV ()

Thus, the magnitude and sign of the control signal v is linear on with the magnitude and detuning sign of Y, equal to

Y u) C-l / aiL (O) - L-C - 1) / toL,

and does not depend on the quality of the circuit zero sequence.

Due to the unambiguous monotonous dependence of the control signal on the detuning of Y in the device, using the setup anticipation unit 15 and the adder 12, the predetermined detour of the zero sequence is quite simple. When using block 15 as a functional converter

using blocks 12 and 15 can be

implement a software adjustment correction to take into account the nonlinear current-voltage characteristic of an arc-suppressing reactor with biasing when it jumps from normal network operation to single-phase closing modes

When a single-phase closure occurs, the specified mode — the mode recognition mode (by transforming the neutral bias voltage of some given level equal to, for example, 15% of the nominal phase voltage), the signal from the output of block 16 arriving at the second input of the unit

-

13, prohibits a change in the inductive type of an arc-suppressing reactor. As a result, in the single-phase closure modes, that loop loop setting is retained.

) five

ten

15

20

25

thirty

35 40

-

45

50

55

left after-run, which was made in the normal mode of the network

Claims (1)

The proposed device, having one relay link, is capable of detuning the zero sequence of any streamer, does not require any additional devices for detecting the detuning sign of the resonant state of the loop, and therefore, without much addition, it can be used both for detuning measurement and for automatic tuning arc extinguishing reactor. Invention Formula Phase regulator for automatic maintenance of capacitive current compensation conditions in cable networks with arc suppression reactor, containing network-connected artificial asymmetry unit and reference signal sensors and neutral bias voltage, scale converter, first adder, burdock, multiplier, the first and second low-pass filters, the detuning indicator, the resonant state of the zero-sequence loop, the second adder, the setpoint setting unit, the control unit of the arcing reactor ohm and neutral mode recognition unit, the scale converter, the first adder, the relay link and the first low-pass filter are connected in series and connected to the first input of the second adder and the indicator input, the second input of the second adder is connected to the output of the setpoint setting unit, and its output is the control unit of the arc-suppressing reactor, to the second input of which the output of the mode recognition unit is connected, the output of the neutral bias voltage sensor is connected to the inputs of the mode recognition unit and the large-scale direct current the generator, the sensor output of the reference signal is connected to the second input of the multiplying link, the output of which is connected to the input of the second low-pass filter; the output of this filter is connected to the second input of the first adder, characterized in that, to simplify and improve reliability, the output of the relay link is also connected with the first entry of the multiplying link.,