JP2003032882A - Circuit for preventing extension of hindrance caused by high-voltage grounding of dc electric railway - Google Patents

Abstract

PROBLEM TO BE SOLVED: To see that as far as the feeder of adjacent another substation does not stop by the rounding of the DC bus of one substation or the grounding of the low-resistance external wire within a pipe. SOLUTION: In a series circuit of a discharge circuit 1, the discharge voltage is smaller than the working voltage of a DC high-voltage grounding relay 42, and a resistor 43 for current detection is provided in place of a DC high-voltage grounding relay between the grounding mat 23 and the rail 21 of the substation 5. Even if the discharge gap discharge electricity by the grounding 24 of the DC bus of the substation 5 and an AC breaker 6 and DC breakers 10 to 13 become off, that relay 42 does not work since the discharge voltage of the discharge gap 1 is lower than the working voltage of the DC high-voltage grounding relay 42 in the substation 28, and the feeder continues without disconnecting an AC breaker 29 and DC breakers 33 to 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC electric railway in which the AC circuit breaker or the DC circuit breaker is cut off to another substation when a DC bus grounding of a substation or a low resistance ground fault occurs in the substation. Belong to the field of technology to make sure it does not fall.

[0002]

2. Description of the Related Art FIG. 3 shows a situation of power feeding from a substation of a conventional DC electric railway. The substation 5 receives high-voltage AC from the external AC transmission line, passes through the AC circuit breaker 6 and then the transformer 7
The voltage is stepped down, and is rectified by the rectifier 8 to be fed from the DC bus 9 to each section of the overhead line. For example, it is fed to the section A of the ascending overhead line via the DC circuit breaker 10 and the overcurrent relay 14, and to the section B of the ascending overhead line via the DC circuit breaker 11 and the overcurrent relay 15.
Electric current is applied to the section E of the down line via the DC breaker 12 and the overcurrent relay 16, and to the section F of the down line via the DC breaker 13 and the overcurrent relay 17. Thus, for example, direct current 1
The plus side of 500 V is connected to the overhead lines 18 and 19, and the minus side of the 500 V is connected to the rail 21 to drive the motor of the train 20.

On the other hand, a grounding mat 23 is provided inside the substation, and a DC high voltage grounding relay 22 is connected between the grounding mat 23 and the rail 21. This is because when the DC bus 9 is grounded to the grounding mat 23 (DC bus 24) or the overhead wire has a low resistance ground fault (external low resistance ground 25), the AC circuit breaker 6 and It is a relay for interrupting the DC breakers 10 to 13 to stop feeding.

In the case of a DC bus ground fault, when the DC bus is grounded by connecting it to the ground mat connection terminal for safety during some construction work, or when the user forgets to remove it after the construction work, a mouse or a snake. An animal, such as an animal, hangs between the DC busbar and the ground mat connection terminal on the surface of the ground, or the arc of the DC circuit breakers 10 to 13 activated during an external ground fault does not extinguish well and fluctuates irregularly. It occurs when an arc jumps between the bus bar and the ground mat connection terminal.

Further, a low-resistance ground fault of the overhead line occurs when an iron wire driven deep into the ground comes into contact with the overhead line when civil engineering work is being performed near the overhead line. When such a DC bus ground fault 24 or an external low resistance ground fault 25 occurs,
A DC high voltage is applied to the DC high-voltage grounding relay 22 connected between the grounding mat 23 and the rail 21 through the grounding mat 23, and by operating this, the AC breaker 6 and the DC breakers 10 to 13 are all cut off to the overhead line. All electric power is stopped. In this way, the DC high voltage ground relay 2
At the substation where the AC circuit breaker 6 and the DC circuit breakers 10 to 13 are cut off due to the operation of 2, the maintenance personnel go to the substation,
After investigating and removing the cause of the ground fault, each circuit breaker will be turned on again.

Although the substation 5 has been described above, in the case of the adjacent substation 28 as well, when a DC bus ground fault occurs in the substation premises or an external low resistance ground fault occurs in the overhead line during feeding. The same situation as in the case of substation 5 is reached.

[0007]

However, when a ground fault occurs due to the substation 5, the DC high voltage ground relay 2
2 operates to cut off the AC circuit breaker 6 and the DC circuit breakers 10 to 13, and the DC high-voltage grounding relay 42 of the adjacent substation 28 operates to operate the AC circuit breaker 29 and the DC circuit breaker of the substation 28. There is a problem that the circuit breakers 33 to 36 are cut off, and the train in the section where the power is supplied from the substation 28 as well as the section where the power is supplied from the substation 5 may be stopped. The reason is that the high voltage applied to the grounding mat 23 due to the ground fault is transmitted to the grounding mat 43 of the adjacent substation 28 through the ground and the DC high voltage grounding relay 42 connected between this and the rail 21 is activated. This is because. Although there are two substations in Fig. 3, there is a possibility that a total of three substations on both sides of the accident substation will be stopped due to the accident.

In such a case, in addition to the problem that the operation of the train is stopped over a wide range, the maintenance personnel go to two or three substations to investigate and eliminate the cause of the ground fault. There is a problem that it takes a long time to recover because it cannot be re-injected, which causes a serious operation failure.

In view of the above-mentioned problems of the prior art, an object of the present invention is to prevent a circuit breaker from disconnecting due to a chain reaction between adjacent substations even if a ground fault occurs in one substation. Another object of the present invention is to provide a circuit for preventing expansion of trouble, which allows a command to be immediately issued again from the command station to recover even if a circuit breaker in an adjacent substation is disconnected due to a chain reaction.

[0010]

In order to achieve the above-mentioned object, a circuit for preventing expansion of troubles due to a DC electric railway high voltage ground fault according to the present invention has the following constitution. A first structure is a circuit for preventing expansion of a trouble due to a DC electric railway high voltage ground fault, which is characterized by having the following means. (B) A discharge gap connected between the grounding mat in the substation of interest and the rail in the distribution section, the discharge voltage of which is the difference between the grounding mat in the adjacent substation and the rail in the distribution section of the substation. Discharge gap lower than the operating voltage of the DC high-voltage grounding relay connected between them (b) With the operation of the DC high-voltage grounding relay due to the occurrence of a high-voltage ground fault on the adjacent substation side, the discharge gap of the substation of interest discharges. Remote control means to reclose the circuit breaker of the substation of interest at the command station

The second structure is a circuit for preventing expansion of trouble due to a DC electric railway high voltage ground fault, which is characterized by having the following means. (A) Discharge gap connected between the grounding mats inside the substation and the rails of the electricity section in each adjacent substation (b) Discharge that detects the discharge current of each discharge gap when a high voltage ground fault occurs Current detecting means (c) Discharge current remote monitoring means (d) for remotely monitoring the discharge current at the command station. Remote commanding means for reclosing the circuit breaker at the substation with a small discharge current at the command station.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The first embodiment of the present invention is a substation of interest, in which the discharge voltage is different from that of the conventional DC high-voltage grounding relay and the grounding mat in the adjacent substation and that of the substation. A discharge gap having a voltage lower than the operating voltage of the DC high-voltage grounding relay connected to the rail of the electricity section is provided. By doing so, if a DC bus ground fault or a low resistance external ground fault occurs at the substation of interest, and a high voltage is applied to the discharge gap, the AC breaker or DC breaker of the substation of interest will be discharged. However, since the discharge voltage is lower than the operating voltage of the DC high voltage ground relay of the adjacent substation, that voltage is applied to the DC high voltage ground relay of the adjacent substation through the ground mat of the ground and the adjacent substation. Even if it does, the DC high-voltage grounding relay will not operate, so the AC breaker or DC breaker at the adjacent substation will not be disconnected. That is, even if a ground fault occurs on the substation of interest, adjacent substations do not stop operating in a chain.

On the contrary, a ground fault occurs on the adjacent substation side and a high voltage is applied between the ground mat and the ground and the rail. This causes a high voltage to the discharge gap through the ground and the ground mat of the substation of interest, resulting in discharge. It is not that the AC breaker or DC breaker of the substation of interest does not break due to
Since the DC high-voltage grounding relay of the adjacent substation is operating, it is determined that the ground fault has occurred in the adjacent substation and not the focused substation, and the AC breaker of the focused substation , The DC circuit breaker will be re-closed immediately from the command center, and power will be resumed in a short time. Therefore, as a result, the long-term power supply stop does not extend to other substations.

The above is the case where the ground mat of the substation of interest and the ground mat of the adjacent substation are ground and not connected by a conductor. For example, a substation exists in an underground tunnel such as a subway. In that case, if the grounding mat is connected by the reinforcing bars of the tunnel structure, or if the substation is receiving power from the same transmission line, its sheath ground is dropped to the grounding mat of each substation, so after all The grounding mat may be connected by the sheath of the power transmission line.

In such a case, even if the discharge voltage of the discharge gap of the substation of interest is lower than the operating voltage of the DC high voltage ground relay, a resistor for DC detection is inserted between the discharge gap and the ground mat. The potential of the grounding mat becomes higher, and it is applied to the grounding mat of the adjacent substation through the reinforcing steel of the tunnel structure and the sheath of the transmission line, and the DC high-voltage grounding relay of the adjacent substation operates and the AC breaker or DC The breaker may be cut off.

In this way, when the DC high-voltage grounding relay operates, it is not possible to reclose the circuit breaker by remote control from the command station even if there is no ground fault in the substation pipe. Must go to that substation and re-inject it. In the end, if a ground fault accident occurs at the substation of interest, the adjacent substation may also be involved and the impact of the accident may increase.

Therefore, in the second embodiment of the present invention, a discharge gap and a discharge current detecting means are provided between the ground mat and the rail in each of the adjacent substations, and a command is issued. A discharge current remote monitoring means for remotely monitoring the discharge current is provided, and the discharge currents are compared, and a remote operation means for reclosing the circuit breaker to the smaller substation is provided.

By doing so, a ground fault occurs at the substation of interest, the discharge gap discharges and the breaker is disconnected, and the high voltage of the grounding mat with respect to the rail causes the high voltage of the grounding mat to the adjacent substation through the rebar / transmission line sheath. Even if the discharge gap of the substation is discharged by being transmitted to the grounding mat of the substation and the breaker may be disconnected, there is resistance of the rebar / transmission line sheath and rail, so the substation of interest as a ground fault substation. The discharge current at the adjacent substation is smaller than that at. this,
Remotely monitor the discharge current of both substations at the command station, compare both discharge currents, and judge that the substation with a small discharge current is a substation with no ground fault accident, and use the remote control means of the command station. Since the circuit breaker will have to be re-closed, it is unlikely that maintenance personnel would have to go to the substation and re-close the circuit breaker, as in the case of using a DC high voltage earth relay. It is possible to prevent the influence of the accident from expanding.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a circuit for preventing an expansion of a trouble due to a DC electric railway high voltage ground fault according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a circuit of an embodiment of the first configuration of the present invention. Now, in the substation 5, the DC busbar 9 has a ground fault to the grounding mat 23 (DC busbar grounding fault 24), or the overhead wire fed from the substation 5 has a low resistance equivalent to that of the grounding mat 23. Let's look at the case of a ground fault (external low resistance ground fault 25). When such a ground fault occurs, a high DC voltage is applied to the grounding mat 23 and the rail 21 is a minus line (return line).
1 and the grounding mat 23 through the current detecting resistor 43, a high voltage is applied to the discharge gap 1 to cause discharge and a large current flows. At this time, the AC breaker 6 and the DC breakers 10 to 13 However, the discharge voltage of the discharge gap 1 is lower than the operating voltage of the DC high voltage grounding relay 42 of the substation 28, and there is the resistance of the ground 26 between the grounding mat 23 and the grounding mat 43. Relay 42
Does not work, and eventually the ground fault on the substation 5 side is adjacent to the substation 2
It does not affect 8.

On the contrary, when a DC bus ground fault or a low resistance external wire ground fault occurs in the substation 28, the DC high voltage ground relay 42 operates and the breaker of the substation 28 is disconnected. The high voltage applied to the grounding mat 43 is the earth 26
There is a case where the discharge gap 1 of the substation 5 is discharged through the ground mat 23 through the ground mat 23. When discharged, the AC circuit breaker 6 and the DC circuit breakers 10 to 13 are disconnected.

However, in this case, since the DC high-voltage grounding relay 42 is operating as described above, it is known that the command station has a ground fault at the substation 28 and is not an accident at the substation 5. Since the circuit breaker of the substation 5 is re-closed immediately after the command station, the operation of the electric train in the substation 5 is hardly affected.

In this way, when the ground mats of each substation are not connected by conductors but only to the ground, the discharge gap 1 and the current are replaced at a certain substation 5 in place of the conventional DC high voltage ground relay. When the detection resistor 43 is used, even if the adjacent substation 28 remains the conventional DC high voltage grounding relay 42, even if a DC bus ground fault or the like occurs at the certain substation 5, the adjacent substation 28, and conversely, when a DC bus ground fault or the like occurs in the adjacent substation 28, even if the discharge gap 1 of the certain substation 5 discharges and the circuit breakers are disconnected, the command station Since it can be re-introduced immediately from, it will have virtually no effect.

On the other hand, the ground mat 23 of the substation 5 and the ground mat 43 of the substation 28, such as in a subway,
It is connected by the reinforcing steel of the reinforced concrete of the tunnel, or the ground mats are connected by the sheath of the transmission line by grounding the sheath of the power transmission cable for transmitting power to each substation to the ground mat at each substation. In this case, as shown in FIG. 1, one substation 5 uses the discharge gap 1 and the other substation 28 uses the DC high-voltage grounding relay 42.
Then, when a DC bus ground fault occurs in the substation 5, the discharge gap 1 is discharged, and the AC breaker 6 and the DC breaker 10 to 10
When 13 is disconnected, the DC high voltage grounding relay 42 of the substation 28 is activated and the AC breaker 29 and the DC breakers 33 to 3 are
6 may be disconnected, and in that case, maintenance personnel must go to the substation 5 in addition to the substation 5 where the ground fault occurred, and re-close the circuit breaker.
The trains in the area will also stop operating.

It is considered that this is because the high voltage applied to the grounding mat 23 due to the ground fault is easily transmitted to the grounding mat 43 by the reinforcing bars and the sheath. Therefore, even in such a case, it is the second configuration of the present invention to prevent the expansion of the influence due to the ground fault.

FIG. 2 is a diagram showing a circuit of a second embodiment of the present invention. The difference from FIG. 1 is that a discharge gap 3 and a current detection resistor 4 are used in place of the DC high voltage grounding relay 42 of FIG. In addition, although the grounding mat 23 and the grounding mat 43 are connected by a reinforcing bar / transmission line sheath 44, etc., this is not a requirement, and even in such a case, it is possible to prevent expansion of the range of suspension of train operation. Is.

In such a case, the DC high voltage applied to the grounding mat is applied to the grounding mat of the other substation through the rebar / transmission line sheath etc. 44 regardless of which substation the DC bus ground fault occurs. . Therefore, not only the discharge gap of the substation in which the ground fault has occurred but also the discharge gap of the other substation may be discharged, and at that time, the breaker is disconnected in any of the substations.

At this time, the discharge current detected by the current detecting resistors 2 and 4 of each substation is monitored by the discharge current remote monitoring means of the command station. This discharge current is larger in the substation in which the ground fault has occurred, and smaller in the other substation in which the ground fault has not occurred. The reason is that for the discharge gap of the substation in which the ground fault has not occurred, the resistance of the rail 21 between the two substations and the reinforcing bars are more than that for the discharge gap of the substation in which the ground fault has occurred. Since the resistance of the transmission line sheath 44 and the like will be in series, the discharge current will be reduced accordingly.

Therefore, the command station compares the magnitudes of the discharge currents monitored by the discharge current remote monitoring means, judges that the smaller substation is a substation in which no ground fault accident has occurred, and immediately operates the remote control means. Restart the circuit breaker that was disconnected due to. In this way, the circuit breaker may be disconnected at the substation where the ground fault has not occurred, but since maintenance personnel do not go to the substation as soon as possible, it will be restarted as soon as possible. You will not receive it.

[0029]

As described above, the DC / Electrical railway high voltage ground fault preventive circuit of the present invention is used in place of a conventional DC high voltage ground relay in one of a plurality of substations or in an adjacent substation. Since a discharge gap whose discharge voltage is smaller than the operating voltage of the DC high voltage ground relay and discharge current detection means in series with it are used, a discharge gap is provided if there is no conductor connection between the ground mats of the substation. Even if a DC bus ground fault occurs in the substation and the discharge gap is discharged, the DC high voltage ground relay of the adjacent substation is not activated, and there is an advantage that the ground fault does not affect. Conversely, if a DC bus ground fault occurs at an adjacent substation and the DC high-voltage grounding relay is activated, which causes the discharge gap to discharge and the breaker at that substation to break, the DC High If the operation of the earth relay is detected, it can be judged that the ground fault accident is an accident of the substation where the DC high voltage earth relay is installed.Therefore, for the substation where the discharge gap is installed, immediately from the command center. Since the circuit breaker can be re-closed, there is an advantage that the operation of the train in the substation will not be practically disturbed.

Further, by setting discharge gaps in both of the adjacent substations, the ground mats of both substations are connected by conductors, and one ground fault causes the other discharge gap to be discharged. Even when the circuit breaker is turned off, the discharge current can be monitored at the command center and the larger one can be judged to be the substation where the ground fault occurred. Since it can be put into operation, there is an advantage that it does not practically hinder the operation of trains inside the substation.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a circuit of a second configuration example of the present invention.

FIG. 3 is a diagram showing a situation of feeding from a substation in a conventional DC electric railway.

[Explanation of symbols]

1 discharge gap 2 Current detection resistor 3 discharge gap 4 Current detection resistor 5 substation 6 AC breaker 7 transformer 8 rectifier 9 DC bus 10, 11, 12, 13 DC breaker 14, 15, 16, 17 Overcurrent relay 18 ascending overhead line 19 down line 20 train 21 rails 22 DC high voltage earth relay 23 Ground mat 24 DC Bus Ground Fault 25 Outside line low resistance ground fault 26 Earth 27 minus line 28 Substation 29 AC breaker 30 transformer 31 Rectifier 32 minus line 33,34,35,36 DC circuit breaker 37,38,39,40 Overcurrent relay 41 train 42 DC high voltage earth relay 43 Ground mat 44 Reinforcing bar / transmission line sheath, etc.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinichi Hase             38-8, Hikarimachi, Kokubunji, Tokyo 38 Foundation             Corporate Railway Technical Research Institute (72) Inventor Toshikatsu Ito             1-7-24 Kita, Kunitachi, Tokyo             Earl Research Institute Electric System F-term (reference) 5G013 AA02 AA04 BA02 CB04 DA03

Claims (2)

[Claims] 1. A circuit for preventing expansion of a trouble caused by a DC electric railway high voltage ground fault, comprising the following means. (B) A discharge gap connected between the grounding mat in the substation of interest and the rail in the distribution section, the discharge voltage of which is the difference between the grounding mat in the adjacent substation and the rail in the distribution section of the substation. Discharge gap lower than the operating voltage of the DC high-voltage grounding relay connected between them (b) With the operation of the DC high-voltage grounding relay due to the occurrence of a high-voltage ground fault on the adjacent substation side, the discharge gap of the substation of interest discharges. Remote control means to reclose the circuit breaker of the substation of interest at the command station 2. A circuit for preventing expansion of a trouble caused by a high voltage ground fault of a direct current electric railway, comprising the following means. (A) Discharge gap connected between the grounding mats inside the substation and the rails of the electricity section in each adjacent substation (b) Discharge that detects the discharge current of each discharge gap when a high voltage ground fault occurs Current detecting means (c) Discharge current remote monitoring means (d) for remotely monitoring the discharge current at the command station. Remote commanding means for reclosing the circuit breaker at the substation with a small discharge current at the command station.