JPS62177463A - Fault point locating system - Google Patents

Abstract

PURPOSE:To locate the distance to a fault point with high accuracy by setting simultaneous equations based upon voltage and current on this system and current information on the opposite terminal. CONSTITUTION:The absolute values of the voltage VP and current IP at the installation point of a fault point locating device (FL) are found by circuits 1 and 2. Further, a circuit finds the phase difference theta between the voltage VP and current IP, a circuit 4 finds the absolute value of an opposite-terminal current IO, and a circuit 5 finds the phase difference delta between the currents IP and IQ. Further, the sine component of the output phase of the circuit 3 and the output of the circuit 2 are integrated 6 and a sine component obtained by subtracting the phase difference delta of the circuit 5 from the phase difference theta of the circuit 3 and the output of the circuit 4 are integrated 7. Further, the since component of a power transmission line angle alpha and the output of the circuit 2 are integrated 8 and a sine component obtained by subtracting the output of the circuit 5 from the line angle alpha and the output of the circuit 4 are integrated 9. An arithmetic circuit 10 integrates the sum of the output of a circuit 6 and the output of a circuit 7, and the output of the circuit 1 and also integrates 11 the sum of the output of the circuit 8 and the output of the circuit 9 with the output of the circuit 2. Then, the value obtained by integrating the output of a circuit 11 and impedance per unit length of the power transmission line is divided 12 by the output of the circuit 10 to locate the distance to the fault point with high accuracy.

Description

[Detailed Description of the Invention] The present invention relates to a fault point locating method fζ, and the present invention relates to a fault point locating method fζ, which can be used to locate a power transmission line with high accuracy based on current and pressure information at its own end and current information at the other end. This paper relates to a fault point locating method for locating a fault point.

(Prior art) Conventionally, this type of failure point locating method was developed using the
There was one shown in No. 0262.

Figure 2 is an equivalent circuit diagram of a power system when a failure occurs to explain the conventional invention. In Figure 1, Ep and EQ are P terminal and Q.
The power supply voltage at the end, zgp and ZgQ are the back impedances at the P and Q ends, and VP and vQ are the voltages at the P and Q ends.

IP, IQ are the currents flowing from P and Q terminals to the fault point, R
F is the fault point resistance, 20 is the fault locator (hereinafter referred to as FL), eZ is the impedance from the FL installation point to the fault point, a is the distance from the FLL installation point to the fault point, and Z is Indicates the impedance per unit length of the power transmission line. (L-12 is the impedance from the failure point to the Q end, and L is the distance □ between the P end and the Q end.

Next, the concept of the conventional method will be explained.

In Figure 2, the relationship between voltage and current is Vp=#ZIp+RF(Ip+Ig)
-(1)VQ= (L-#)ZIQ +RF(IP+
IQ) - (2). Therefore, when determining the impedance up to the failure point from the voltage and current information at the FLL point, it can be determined by dividing the voltage by the current as shown in equation (3) below.

In the case of RF-0 in equation (3), eZ is obtained, where Z
Since the impedance per unit length of the power transmission line is a known value, the distance ft e to the fault point can be determined. However, in the case of a failure in an actual system, RF is an unknown value and RF~0, so the two items in equation (3) become errors.

In the conventional invention, in order to eliminate this error, fault point location is performed by obtaining current/voltage information at the own end (P end) and the opposite end (Q end).

That is, by eliminating the value of RF from equations (1) and (2), Vp-
Vg=/+Z(Ip+1□)−LZI□ Therefore, the distance e to the failure point is calculated from the following equation (4).

(Problem to be solved by the invention) Since the conventional failure point locating method is configured as shown in equation (4), it requires voltage and current information of the own end and the opposite end. The disadvantage was that the current information had to be manually recorded, and the transmission capacity was large.

This invention was developed to solve the above-mentioned problems, and eliminates the need for voltage information at the other end, and allows the distance to the failure point to be determined using only the voltage and current information at the own end and the current information at the other end. The purpose of this invention is to provide a failure point locating device that can locate with high precision.

(Means for Solving the Problem) The fault point locating device according to the present invention decomposes the voltage at the FLL point into a sine component and a cosine component using the current at the FLL point as a reference, and divides the voltage drop component due to the fault current into equal parts. By formulating simultaneous equations, the distance to the failure point can be determined by solving the equations.

[Operation] In the method of this invention, two equations are established by obtaining two quantities for the sine component and cosine component of the voltage at the PLL point, so even if there is no voltage information at the other end, high accuracy can be achieved. can be located.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, l is a circuit for calculating the relative value of voltage Vp at the FLL point, 2 is a circuit for calculating the absolute value of 'a ML I p at the FLL point, and 3 is i for calculating the phase difference θ between Vp and IP.
4 is a circuit for calculating the absolute value of the other end current IQ, 5 is I
A circuit for calculating the phase difference δ between P and IQ. 6 is a circuit for calculating 1Iplsinθ from the outputs of 2 and 3. 7 is a circuit for calculating ll01sin(ff-a) from the outputs of 3 to 5. 8 is a circuit for calculating 1Iplsinα. where a is the line angle of the transmission line and the impedance per unit length Z = r + jx, the value shown by α = jan' (-), 9 is the output of 4 and 5, 10 is 1Vpl (1lplsinθ+If
01sin(θ-J)), 11 is 1IplNIplsinα+l1g1si from the outputs of 2, 8, and 9.
n(α-β)), 12 is a circuit that divides the integrated value of the output of 11 and the impedance Z per unit length of the transmission line by the output of the above 10 circuits, 18 is the fault name from FL installation. Indicates the terminal that outputs the distance.

Next, the concept of the present invention will be explained.

From the equivalent circuit diagram of the power system when a failure occurs in Figure 2, F
The voltage vP at the LL point is the voltage drop component gztp of the impedance eZ up to the failure point due to the current IF at the FLL point.
Since it is the sum of the voltage drop component Rp (Ip+I□) of the fault point resistance RF due to the sum of the currents IQ and IP from the other end, it can be shown as shown in FIG.

In the figure, α is the line angle of the power transmission line, impedance per unit length Z = r + j The phase angle with respect to IP is indicated by the phase difference.

From Figure 3, the following (5) is obtained from the sine and cosine components of vP.
, +61 formula holds true.

#ZIIplsinα+RpHqlsinδ=lVpl
sinθ ・(5) eZI Ip 1cosα+Rpl
IPl+RFIIQICO8δ= 1Vplcosl
! 7-=(6)(5), +6) If the equation is rewritten by the determinant f, the following equation (7) is obtained.

Therefore, the distance e to the failure point can be determined by the following equation (8).

From this, when information on the current IQ at the other end is obtained, all the constants in the equation become known, so the distance to the failure point can be calculated even without voltage information at the other end. In addition, since there is no fault point resistor RF in one set, errors due to voltage drop components occurring in the RF section do not occur (it can be seen that highly accurate location can be achieved).

Although the above embodiment has been explained using a single phase, it goes without saying that it can also be applied to a three phase case.

Further, in the above embodiment, the distance to the fault point was determined by obtaining the actance up to the fault point, but it is clear from equation (7) that the fault point resistance RF can also be determined.

(Effects of the Invention) As described above, according to the present invention, it is possible to calculate the distance to a failure point using the voltage and current information of the own end and the current information of the opposite end, so the transmission capacity can be reduced, and the This has the effect of obtaining highly accurate distance measurement without any distance measurement errors due to point resistance.

[Brief explanation of drawings]

Figure 1 is a block diagram showing a failure point locating device according to one embodiment of this redundancy, Figure 2 is an equivalent circuit diagram of the power system at the time of failure, and Figure 8 depicts the current and voltage components of Figure 2. It is a diagram.

Claims (1)

[Claims] In a two-terminal power transmission line having a power supply at both ends, first and second circuits that derive the absolute values of the system voltage and current at the own end, and a third circuit that derives the phase difference between the voltage and the current at the own end. , a fourth circuit that derives the absolute value amount of the current at the other end, a fifth circuit that derives the phase difference between the current at the other end and the current at the other end, and the third circuit described above.
a sixth circuit that integrates the sine component of the output phase of the circuit and the output of the second circuit; a sine component of the value obtained by subtracting the output of the fifth circuit from the output of the third circuit; a seventh circuit that integrates the output of the fourth circuit, an eighth circuit that integrates the sine component of the line angle of the power transmission line and the output of the second circuit, and a fifth circuit that integrates the output of the second circuit based on the line angle of the power transmission line. A ninth circuit that integrates the sine component of the value obtained by subtracting the output of and the output of the fourth circuit.
a tenth circuit that integrates the output of the first circuit with the sum of the output of the sixth circuit and the seventh circuit, the output of the eighth circuit and the output of the ninth circuit. an eleventh circuit that integrates the output of the second circuit into the sum; and a value that integrates the output of the eleventh circuit and the impedance per unit length of the power transmission line and divides it by the output of the tenth circuit. A fault point locating method characterized by providing a twelfth circuit and locating the distance to the fault point.