JPH0238872A - Fault point locator - Google Patents

Abstract

PURPOSE:To locate a fault point economically at a high reliability by performing an outputting being switched with the results of a gauge mark of a fault point based on a comparison between each circuit current and a criterion value for the presence of a fault current. CONSTITUTION:When a fault F occurs in a circuit L1, a signal is outputted based on circuit currents I1 and I2 from an input circuit 1 and a partial voltage PD of a power source voltage V. Fault locators 4 and 5 using a shunt ratio method and an impedance method output the results A nd B of locating a fault point to respective AND circuits 7 and 8. Comparators 2 and 3 compare current values I1 and I2 with a criterion value K. Breakers CB11 and CB12 are at a 'making position', I1>K and I2>K are given previously. Therefore, an OR output 6 is zero and the results A of the location obtained by the shunt ratio method are outputted via the AND circuit 7 and an OR circuit 9. When one of the breakers is at a 'breaking' position, I1<K or I2<K is given and the OR output 6 is produced and the results B of the location as obtained by the impedance method are outputted via the AND circuit 8 and the OR circuit 9. This eliminates a large error in the location thereby enabling economical location without use of a signal of the breaker on the opposed end side.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a failure point locating device for a parallel two-line power transmission line.

B2 Summary of the Invention This invention provides a fault point locating device equipped with two fault point locating devices using a current ratio method and an impedance method for parallel two-line power transmission lines. A comparison device is provided to compare the respective judgment values for determining the presence or absence of current, and based on the judgment results of this comparison device, 2.
When it is determined that the line is in a combined state, the result of locating the fault point using the current ratio method is output, and when it is determined otherwise, the result of locating the fault point using the impedance method is output.

C1 Conventional technology A fault point locating device that locates the distance of a fault point that has occurred in a power transmission line using the current and voltage obtained from current transformers and voltage dividers installed in the power system, comparing two parallel power transmission lines. There are two well-known methods:

(+) A shunt ratio method that locates the failure point using the shunt ratio of the fault type^ in each line of two parallel lines.

(2) Impedance method that measures the impedance up to the failure point and locates the failure point.

However, these methods have the following advantages and disadvantages.

The shunt ratio method is used particularly in the case of single-line ground faults in high-resistance grounding systems using the impedance method, but even with two parallel lines, it is impossible to locate the line unless the two lines are used together.

Although the impedance method allows for location without using two parallel circuits, it is inferior to the shunt ratio method, especially in single-line ground faults in high-resistance grounding systems.

For this reason, conventional fault point locating equipment for parallel two-circuit transmission lines
It is common practice to use the shunt ratio method when two parallel circuits are used together, and to use the impedance method otherwise.

To explain this conventional example with reference to FIG. 2, the location results A and B of the fault point locating device 4 based on the shunt ratio method and the fault point locating device 5 based on the impedance method are determined by one of the AND circuits 11 and I2, respectively. input to the terminal. Also the first
．． The “on” signals of the circuit breakers CBIL and CB2L of the second line are input respectively.AND circuit circuit l specific power terminal is Moeki A
It is connected to the other terminal of the ND circuit 11 and the other terminal with an inverter of the AND circuit 12. However, circuit breaker C
B l 1. , and CB2L are both "person", the location result A from the fault point location device 4 using the split flow ratio method is A.
It passes through the ND circuit 11 and is output from the OR circuit 13.

Also, only one of the shutoff ICBIL or CB2L is "on".
In this case, the location result B from the fault location location device 5 using the impedance method passes through the AND circuit +2 and is sent to the OR circuit 13.
It is output from In other words, if both circuit breakers CBIL and CB2L are operated by one person, then the result of the split ratio method is used because it means that two circuits are used together, and if only one of the circuit breakers is operated by one person, then jIa (for #) is used. Since he is not deaf, the results of the impedance method are used.

D Problems to be Solved by the Invention However, since the "on" information of this circuit breaker is only from the circuit breaker at the end of the transmission line, even if both of these are "people", the circuit breaker at the opposite end cannot be disconnected. If the utensil is ``Cut J'', 2
Even though the lines are not used together, the split ratio method is used, resulting in a large error in orientation due to the following reasons.

The principle of the shunt ratio method is that if there is an accident F at point xkx of line L1 as shown in Figure 3, the transmission itt per Ikx
If the resistance of the wire is R, then V = I + x R = I t (2Q x )
Since the relationship R holds, the distance X to the accident point F can be determined from this equation as x=212It/(Il+It).

By the way, as shown in Fig. 4 (a), the opposite side circuit breaker CB is
If it is set to ``off'', r,=o, and the orientation will be incorrect as X=O&Z. Also, as shown in Figure 4 (b), the line [,,
If there is an accident, ■1 = 0, so X = 2
．． (The orientation is incorrect as lkx.

Such orientation errors can be avoided by transmitting the "on" information of the circuit breaker CB at the opposite end to the own end (
, it is economical to transmit the information of the opposite end circuit breaker CI3,
It is disadvantageous in terms of reliability.

This invention was made in view of the above-mentioned problem, and without using the "on" information of the circuit breaker, it is determined whether there is a fault current or not, and when it is determined that both circuits are being used together, the current The present invention provides an accident point locating device that outputs a locating result based on the ratio method, and outputs a locating result based on the impedance method when it is determined that this is not the case.

81 Means for Solving the Problems In order to achieve the above object, the fault point locating device of the present invention is provided with a comparison device that compares each line current with a judgment value for determining the presence or absence of a fault current, and this comparison device Depending on the determination result, the fault point location results using the current ratio method and the fault point location results using the impedance method are switched and output.

21 Effect When two circuits are not used together, the current in the circuit where the fault current does not flow in the event of an accident should be O as shown in Figure 4 (a) and (b), but in reality the current is It does not become O because there is an apparent 0-phase current due to an error or an error in the locator calculation section. Therefore, the current [,.

1. By considering the current that does not become O and the calculation error of the device calculation section, it is possible to detect the presence or absence of a line through which no fault current flows in the event of an accident, that is, the presence or absence of a state in which two lines are not used together.

Therefore, if the above judgment value is set to the maximum value of the line where 81i iX flow does not flow when not used together, an output will be output from the nor-based comparison device, so it can be determined that there is no simultaneous use of two lines. By using the output of the comparison bag jamaro, it is possible to switch and output the fault point location results based on the upstream split ratio method and the fault point location results based on the impedance method.

G. Embodiment To explain the embodiment with reference to FIG. 1, the line L
, and the own ends of circuit breakers C13, and CB?, respectively.
connected to iiv via +. l is the input circuit,
A signal of current 11° for each time from current transformers CT, CT1 and a signal of power supply voltage V from voltage divider PD are input manually. 2 compares the current 11 with the above-mentioned judgment value and obtains [1〈K
Comparison device outputs when 3 is the same <1. A comparator which compares and K and outputs when It<K, 4 and 5 are a fault point locating device using the well-known shunt ratio method and a fault point locating device using the impedance method, respectively. 6 is connected to a comparing device 8.9. 7 is an AND circuit in which the location result A of the failure point locating device 4 is manually input to one input terminal, and the output from the OR circuit 6 is inverted and manually input to the other input terminal. An AND circuit in which the location result B of the failure point locating device 5 is input to one input terminal, and the output from the OR circuit 6 is input to the other input terminal, and 9 is the output from the AND circuit 7.8. is an OR circuit that is manually operated.

If accident F occurs on line 1-r this time, as is well known, the current 11. from input circuit 1 will increase. Fault point locating devices 4 and 5 using the shunt ratio method and impedance method locate the fault point using the signal output of It and the signal output of power supply voltage V, and output the location results to AND circuits 7.8 and 7.8 of A and B, respectively. are doing.

On the other hand, the comparators 2.3 each have a current I3. The Ix signal and the above-mentioned constant faK are respectively compared. This judgment faK is 01
As mentioned in 1, since it is set to the maximum current of the line in which no fault current will flow in the event of an accident when two lines are not used together, if the cutoff i CB , ~CB, 2 are all “in J”, Since I,>K and It>K, comparison device 2.
3 has no output. Therefore, since there is no output in the OR circuit 6, the location result A from the fault point location device 4 using the split ratio method
passes through the AND circuit 7 and is output from the OR circuit 9.

Also, if any one of the circuit breakers C[311-Cn t t is OFF, then I, <! (or l, <K, and there is an output from either comparator 2.3; O
Since the R circuit 6 has an output, the location result B from the fault point locating device 5 using the impedance method is A, and the N D circuit 8
OL (output from circuit 9).

1-1. Effects of the Invention Since the present invention is constructed as described above, it produces the effects as described below.

When locating the fault point of a mourning two-circuit power transmission line, switching between the fault point location results using the current ratio method and the impedance method is performed by detecting the presence or absence of a fault current and detecting the combined deafness of the two circuits. Conventionally, when two circuits are not used together due to the breaker at the opposite end being turned off, such as in the case of Otsu, where the 1-person signal of the self-ended circuit breaker is used, the fault point location result using the current ratio method is output and used for location. This eliminates the occurrence of large errors. In addition, since it is possible to use the two circuits simultaneously without using the "J" signal of the circuit breaker on the opposite end, it is extremely advantageous in terms of economy, credibility, and intelligence.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram of a conventional device, Fig. 3 is a diagram explaining the principle of the current split ratio method, and Fig. 4 is a circuit diagram showing an embodiment of the present invention.
The figure is an explanatory diagram of the causes of error location in the conventional device. CB...Breaker, CT...Current transformer, FD...Voltage divider, l...Input circuit, 2.3...Comparator, 4...
Fault point locating device using fractional ratio method, 5... Fault point locating device using impedance method.

Claims (1)

[Claims] (1) Fault point locating device using the shunt ratio method and impedance method to measure the distance to the fault point of a fault that occurs in a parallel two-circuit transmission line due to current and voltage from current transformers and voltage dividers installed in the power system Locate each fault point using a failure point locating device,
When using two lines together, outputs the orientation result using the split flow ratio method,
In a fault point locating device that switches to output a location result based on the impedance method when two lines are not used together, a comparison device is installed to compare each line current with a judgment value for determining the presence or absence of a fault current. A failure point locating device characterized in that the output is switched according to the determination result of the comparison device.