JP2541722B2 - Fault location method for DC parallel feeding circuit of electric railway - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fault point locating technique for a DC parallel feeding circuit of an electric railway, and when a short circuit accident occurs in the DC parallel feeding circuit, electricity is supplied to the fault section. The present invention relates to a method of calculating the position of a fault point of a feeder circuit from a feeder failure current data group collected at substations on both sides.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for locating a failure point in an AC high voltage transmission system of a power company. However, in the electric railway, the feeder (feeding) for the trolley line is generally a DC feeder,
It is technically very different from the point that one system is divided into a plurality of sections and two substations are fed in parallel for each section.

In the DC parallel feeding section, the share of the fault current between the adjacent substations changes depending on the magnitude of the feeding voltage value of the substation and the magnitude of the internal resistance value of the substation. Since the situation is not constant, the magnitude of the fault current varies depending on the case even if the fault occurs at the same point. Also,
A condition unique to electric railways is that trains selectively intervene in the form of moving loads. And since the failure situation differs depending on whether there is a train in the failure section,
Locating a fault point in a DC feeding circuit has been an unsolved problem in this field for a long time, and some methods have been proposed so far, but no technique has been put into practical use yet.

[0004]

As described above, all of the methods proposed in the past and not yet put into practical use are limited in application. For example, if there is no train, it can be located. If the voltage of the substation is equal, it can be located, and it was not applicable to complex phenomena in almighty manner. The present invention provides a method capable of locating a failure point in an almighty manner regardless of the difference in the failure conditions at the failure point.

[0005]

[Means for Solving the Problems] Considering the train load as a constant current load, and considering the estimated maximum current value as the fault current assuming that there was no interruption by a circuit breaker when a fault occurred, focus on the current increment based on the fault. To calculate the fault current estimation increment,
The distance from one substation to the fault point can be calculated based on the fault current sharing rate at both substations.

[0006]

The principle of the present invention will be described first. FIG. 2 is a diagram showing a standard DC feeding circuit, in which A and B are substations facing each other, and 1 is an electric line that receives feeding from the substations A and B in parallel. Feeding from substations A and B is 2A,
It is performed through the 2B circuit breaker. 3A and 3B are
It is a failure selection device that outputs a trip signal to the circuit breakers 2A and 2B when reading an electric current and detecting an abnormal current. The failure selection devices 3A and 3B are provided with a CT (current transformer) 4
It is connected to A and 4B and constantly monitors the electric current. In FIG. 2, E indicates a train point and F indicates a feeding circuit failure point. If a failure occurs, the circuit breakers 2A and 2B will trip.

FIG. 3 is an equivalent circuit for steady-state DC analysis of the fault current phenomenon when a fault occurs in FIG. Since the transient analysis is not performed, the inductance of the circuit is omitted. The meanings of the symbols shown in FIG. 3 are as follows. EA, EB: Substation voltage RoA, RoB: Substation internal resistance RA1, RA2, RB: Feeding circuit resistance (r ohm / Km per unit Km, proportional to feeding circuit distance) IA, IB: Substation Noki Denryoku IE: load current of train at point E IF: failure current at point F D: distance between substations d: distance from substation A to failure point F Among the above, it is known in advance , EA, EB, R
Values are oA, RoB, D and feeder resistance r ohm / Km.

It is assumed that a failure occurs at point F and a current IF flows at the failure point. In reality, before the fault current at point F becomes sufficiently large, the circuit breaker at the substation shuts off and the fault current stops flowing. However, here, the fault current is assumed to have not been interrupted by the circuit breaker. Let IF be the current value when it becomes sufficiently large (saturation value) (this is called the “estimated maximum current value”). If the train load at point E is considered to be a constant current load, the circuit phenomenon of FIG. 3 is the same as the circuit phenomenon of (1) of FIG.
(2) is the sum of the circuit phenomena. That is, IA = IA '+ IA "IB = IB' + IB".

With the circuit of FIG. 4B, the fault current IF is
It is divided into IA "and IB".

(Equation 3) And the share ε of the fault current IF of the A and B substations is

[Equation 4] Is.

When the F point occurs at the A substation point (d = 0 point),

(Equation 5) Becomes Here, since ε o (A), ε D (A), and D are known, if the substation share rate ε (A) of the incremental current of each substation due to a failure is obtained, A from Equation (6) The distance from the substation to the fault point can be calculated. This relationship is tabulated and shown in FIG.

In the above description, when there is a train load between the substations, IA'IB 'in FIG. 4 (1) corresponds to the actual feeding current value immediately before the failure and IA' in FIG. 4 (2). ″, IB
″ Corresponds to the actual increment of feeding current due to a failure. On the other hand, when there is no train load between the substations,
In (1), IE = 0, which is shown in FIG.
In (1), a loop current based on the potential difference between EA and EB flows.

By the way, in the actual feeding circuit, since the power supplies EA and EB are obtained by rectifying the AC power by the rectifier, they are disturbed by the reverse current blocking characteristic of the rectifier.
This circulating current does not flow.

That is, when there is no train load, FIG.
IA 'and IB' in (1) do not correspond to the actual feeding current immediately before the failure, but to the "virtual circulating current" obtained by calculation. This "virtual circulating current" is the potential difference between EA and EB and the total resistance value of the loop circuit (RoA + RA1 + RA2 + RB + R).
oB), which is a value known in advance. In addition, I in Fig. 4 (2) when there is no train load
A ″ and IB ″ do not correspond to the actual increment of the feeding current due to the failure, and the actual current increment due to the failure is IA and IB in FIG.
Corresponds to this.

That is, when there is no train load, FIG.
The "virtual circulating current" corresponds to IA 'and IB' in (1), and IA "and IB" in FIG. 4 (2) subtract the "virtual circulating current" from the feeding current increments IA and IB due to the failure. It is equivalent to Therefore, if the presence / absence of train load can be determined from the feeding current phenomenon, IA ″ and IB ″ in FIG. 4 (2) can be calculated, and the failure point can be calculated by the equation (6).

Here, the feeding current value Io (A) immediately before the failure
If both Io (B) and Io (B) are 0, it is considered that there is no train load, and if either one is not 0, it is considered that there is a train load. When Io (A) = Io (B) = 0, The value obtained by subtracting the virtual circulating current from the increment of the actual current at the time of failure is regarded as the current increment due to the failure, and Io (A)
Alternatively, when either one of Io (B) is not 0, the failure point can be calculated by regarding the actual current increment at the time of failure as the current increment due to the failure.

The core of the system principle of the present invention described above is as follows.
Among the electrical phenomena at the time of failure, we focused on the current increment due to the failure, and by doing this, we cleared all the existence of trains, high and low substation voltage, size of substation capacity, difference in fault point situation, etc. Fault location is possible.

FIG. 1 is a conceptual block diagram showing an embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals. 6A and 6B are fault current collecting devices provided on the substation side of the present invention, which are connected to CTs (current transformers) 5A and 5B to constantly monitor the feeding current. The fault current collectors 6A and 6B constantly sample the feeding current, digitize and read the fault current, and fault detectors 7A and 7B that discriminate and detect faults based on the digitally converted data string, and a constant before and after the fault detection time. It is composed of fault current storage units 8A and 8B that store time current data and transmit it to the center.

FIGS. 6 (1) and 6 (2) show examples of current waveforms of fault currents observed at the A and B substations.
The failure detection units 7A and 7B detect the failure at the substation A at point ta in FIG. 6 (1) and the failure at the substation B at point tb in FIG. It is shown that. By storing the data for a certain time before and after the failure detection (actually, 100 ms to 200 ms each before and after the failure), the data necessary for the subsequent arithmetic processing in the center can be collected.

C in FIG. 1 is a central command station, and the central fault point arithmetic unit 9 provided therein has a corresponding fault data extraction unit 10 and an estimated maximum current value Imax based on the extracted data.
Estimated maximum current calculation unit 1 for calculating (A) and Imax (B)
1, and estimated maximum current value and current value immediately before failure Io
Failure current estimation increment ΔImax from (A) and Io (B)
(A), ΔImax (B) are calculated, and the estimated incremental share ratios ε (A) and ε (B) of each substation are calculated, and a predetermined number of substations (voltage value, capacity, internal resistance) input in advance are calculated. , A fault point locating unit 12 that performs the calculation of the above equation (6) based on the feeder circuit constant (electric line resistance per unit length) and the distance between substations. The failure point calculation device 9 does not have to be installed in the central command station, but may be installed in any other place and remotely controlled.

FIG. 7 is a diagram for explaining the operation of the failure point calculating device on the center side. Since the fault current data is sent from each substation as time-stamped data, the corresponding fault data extracting unit 10 roughly matches the A and B data, and then the A substation data is shown in FIG. The point (a) in (1) is found, the point (b) in (2) of FIG. 7 is found from the waveform for the B substation data, and then the estimated maximum current value of the A and B substation data is found. Data groups 701A and 701B for calculating are extracted. This data group extracts data in the same time zone from the A and B data groups. Next, the estimated maximum current calculator 11 calculates Imax (A) and Imax (B) shown in FIG. This I
max (A) and Imax (B) correspond to IA and IB in FIG. 3 used in the explanation of the principle.

In the fault point locator 12, the current value immediately before the fault is
[Io (A), Io (B) in FIG. 7] is calculated, and Io
When (A) = Io (B) = 0, the predetermined virtual circulating current is regarded as Io (A) and Io (B), and Io
If at least one of (A) and Io (B) is not 0, the read value is Io (A), Io
(B), and Imax (A) and Imax (B)
And the fault current estimation increments ΔImax (A), ΔImax
(B) is calculated, then the failure point is calculated by the above-described formula (6), and the result is transmitted to a human by an appropriate output means.

As described above, the present invention solves the problem of locating a fault point in a DC parallel feeder circuit of an electric railway, which could not be put into practical use because a method for withstanding practical use could not be found despite strong demand. Opened the way to. That is, the present invention focuses on the share of the increment of the fault current between the two substations to calculate the fault point by omitting complicated actual conditions such as the presence / absence of a train, the voltage difference at the substation, and the capacity difference. Therefore, in principle, it can be put to practical use, and the search for a failure point and the recovery from an accident can be accelerated.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a standard DC feeding circuit.

FIG. 3 is a diagram showing an equivalent circuit when a failure occurs.

FIG. 4 is an exploded view of the equivalent circuit diagram of FIG. 3 into (1) and (2).

FIG. 5 is a diagram showing a distance relationship to a failure point.

FIG. 6 is a waveform diagram (1) of the fault current as seen at the A substation and a waveform diagram (2) as seen at the B substation.

FIG. 7 is an operation explanatory diagram of the failure point calculation device in the central command station.

[Explanation of symbols]

 1 Train line 1'Rail 2A, 2B Circuit breaker 3A, 3B Fault selection device 4A, 4B, 5A, 5B CT (current transformer) 6A, 6B Fault current collecting device 7A, 7B Fault detection unit 8A, 8B Fault current storage unit 9 Fault point calculator 10 Corresponding fault data extractor 11 Estimated maximum current calculator 12 Fault point locator A, B Substation C Central command station D Distance between substations E Train point F Fault point d A Fault point from substation Distance to F

Claims (2)

(57) [Claims] 1. Corresponding two of an electric railway direct current parallel feeding circuit.
In each of the substations A and B, the feeding circuit current value at the substation outlet is constantly sampled and read to monitor the current change, and a fault detection unit 7A that discriminates and detects a fault when a fault current occurs, 7B and a fault current storage unit 8A for storing and transmitting current data before and after the fault current detection time,
Substation side fault current collector 6A, 6B consisting of 8B
And the central command center C receives the fault current data transmitted from the fault current storage units of the two substations, and extracts the time zone data corresponding to the fault phenomenon from the two current data groups. The data extraction unit 10 and the estimated maximum current value Imax (A), Ima of the fault current from the extracted data.
An estimated maximum current calculation unit 11 that estimates and calculates x (B) and the current values Io (A) and Io (B) immediately before the accident are read,
In the case of Io (A) = Io (B) = 0, Io (A), Io with the virtual circulating current input as the default value.
(B) and when at least one of Io (A) and Io (B) is not 0, the read value is regarded as it is as Io (A), Io (B) and the fault current estimation increment ΔImax ( A) = Imax (A) −Io (A) ΔImax (B) = Imax (B) −Io (B), and then the estimated share of each substation [Equation 1] Is calculated in advance and is input in advance as the default value. The current increment burden ratio at substation A at the time of failure at substation A εo
(A) Incremental current burden ratio at A substation at B substation failure εD
Based on the constants of (A) and distance between substations D, A fault point locating system for an electric railway DC parallel feeding circuit configured by a fault point computing device 9 including a fault point locating unit 12 that calculates the distance from the A substation to the fault point. 2. The fault point computing device 9 is not installed at the central command station, but is installed at one of the two substations or at a point other than the substation so that it can be remotely controlled from the central command station. The fault point locating system for an electric railway direct current parallel feeding circuit according to claim 1, characterized in that.