JPH0478729A - Electric leakage prevention device - Google Patents

Abstract

PURPOSE:To prevent erroneous shut off by making an earth leakage breaker of trunk electric wire an automatic reset type, and energizing a trip coil of an earth leakage breaker of trunk electric wire by a time limit relay and an earth leakage breaker of branch electric wire by an auxiliary relay, in a device of electric car whose power is supplied from a three-phase power supply wire. CONSTITUTION:A three-phase power supply 41 is connected to a trunk electric wire 42 via an earth leakage breaker 1, and a branch electric wire 43 is connected to the trunk electric wire 42 via an earth leakage breaker 2. These earth leakage breakers 1, 2 are of an automatic reset type, and a time limit relay 12, auxiliary relays 11, 21, and trip coils 1aC, 2aC of earth leakage breakers 1, 2 are connected between R and S phases of the three-phase power supply 41 as illustrated in the drawing. The trip coil 1aC of the earth leakage breaker 1 of the trunk electric wire 42 is energized by the time limit relay 12, and the trip coil 2aC of the earth leakage breaker 2 of the branch electric wire 43 is energized by operating contact of the earth leakage breaker 2 and auxiliary relays 11, 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an earth leakage prevention device in power supply equipment for an electric vehicle running along a three-phase power supply line.

[Conventional technology]

Electric vehicle power supply lines are equipped with earth leakage circuit breakers to ensure safety. The earth leakage breaker is a zero-phase current transformer inserted into the power supply line.
When this detects a zero-sequence current higher than the dark value, it opens a no-use breaker installed midway through the power supply line, cutting off the load side from the power supply.

The feeder line has a track branch or a load side branched into multiple branches depending on the length. That is, as shown in FIG.
Trunk power supply connected to! Branch feeder lines 43, 43... are branched from 42, and these are installed along the track as a trolley. An earth leakage breaker is provided on each of the main power supply line 42 and each branch power supply line 43, 43, . . . . A gap called a transition section 44 is provided between the branch sections 43 and 43 in order to keep them from contacting each other. The current collector 46 of the electric car 45 is connected to the transfer section 4 in order to ensure contact.
Equipped with two sets at the front and rear so that even 4.
This is a so-called tandem electronic collector.

If such a collector straddles the front and rear branch feeder lines 43.43, it is impossible for each collector 46.46 (3 phases x 2 sets) to have a uniform contact condition, so each branch feeder line This causes three-phase imbalance and zero-sequence current flows. If this happens, the earth leakage breaker will misidentify that an earth leak has occurred, and the no-use breaker will open.

[Problem to be solved by the invention]

One possible solution to this problem would be to disable the electric vehicle from performing leakage detection for a certain period of time at the transfer area, but depending on the location, it may not be possible to install a position sensor that would make this possible. Further, with such means, in addition to the expense required for arranging the position sensor, modification of the standard specification earth leakage breaker becomes complicated and requires a large amount of expense.

The present invention has been made in view of such circumstances, and if the earth leakage breaker of the main feeder line does not detect the specified zero-sequence current, even if it is detected on the branch feeder line side, it will be caused by an erroneous current at the transfer section. To provide an earth leakage prevention device which prevents erroneous shutoff by not opening a breaker even if there is a problem.

[Means to solve the problem]

The earth leakage prevention device according to the present invention is branched from a three-phase main power supply line equipped with an earth leakage breaker that detects earth leakage and interrupts the circuit by a zero-sequence current detected by a zero-phase current transformer, and is also equipped with an earth leakage breaker. In power supply equipment that supplies power to electric cars equipped with two sets of current collectors that span over two branch feeders and can come into contact with both branch feeders, the earth leakage circuit breaker of the main feeder is of an automatic reset type. , a time-limited relay activated by its operating contact and an auxiliary relay energized are provided, and the contact of the time-limited relay is configured to energize the tripping coil of the earth leakage breaker,
It is characterized in that the tripping coil of the earth leakage breaker is energized by the operating contact of the earth leakage breaker of the branch feeder line and the contact of the auxiliary relay.

[Effect]

In the transfer section, even if an unbalanced current occurs in both branch feeders, the operating contact of the earth leakage breaker on the main feeder does not close, so the trip coil on the branch feeder is not energized.

This can prevent malfunctions at the transfer section. - If a leakage occurs in the main power supply line, the contacts of the earth leakage circuit breakers on the main and technical power supply lines will operate. However, due to the presence of the contact point of the time-limited relay, the circuit breaker on the branch feeder line opens first, and the technical service 1f, * disconnects the leakage position, so the earth leakage breaker on the main feeder line automatically returns, and the circuit breaker on the other healthy Supplies power to the branch power line.

〔Example〕

The present invention will be described below based on drawings showing embodiments thereof.

FIG. 1 shows a circuit of the earth leakage prevention device of the present invention, in which a three-phase power supply 41 is connected to a main power supply line 42 via a no-use breaker 1a of an earth leakage breaker 1. The main power supply line 42 has no-use breakers 2a, 2 of the earth leakage circuit breakers 2, 2...
Branch feeder lines 43, 43... are connected through a..., and there is a transfer section (in Fig. 1) between the ends of the branch feeder lines arranged at adjacent positions. (not shown) is formed.

The earth leakage circuit breakers 1.2 are all of an automatic reset type (2 does not need to be an automatic reset type), and include no-use breakers la, which are installed in each of the main power supply line 42 and the branch power supply line 43.
2a, zero-sequence current transformers 1b and 2b, and a circuit section 1c that performs relay operation etc. based on the zero-sequence current detected by the zero-sequence current transformers 1b and 2b.
, 2c, etc. The circuit portions 1c and 2c are supplied with power from the power supply side through the phases through the no-use breakers la and 2a of the main feeder line 42 and the branch feeder line 43, respectively. Between the R and S phases of the main power supply line 41, the normally open contact 11a+ of the auxiliary relay 11, the time limit contact (normally open contact with a limited opening time) 12a of the time limit relay 12, and the no-use breaker 1a are connected through the above-mentioned phases. Built-in breaker contact 1aa and no-use breaker 1a that open and close in conjunction with this breaker
The series circuit of the tripping coil 1aC is connected in parallel with the series circuit of the normally open contact 1ca whose opening/closing is controlled by the function of the circuit section 1c and the coil 11c of the relay 11. A clock section 12C of a timer 12 and a lamp 13 are connected to the terminal.

On the other hand, between the R and S phases of the branch power supply line 42, a normally open contact 21a of the auxiliary relay 21 is connected via the fuse, a breaker contact 2aa built in the no-use breaker 2a, which opens and closes in conjunction with this breaker, and a no-use breaker. A series circuit of the tripping coil 2aC of 2a, a normally open contact 2ca whose opening/closing is controlled by the function of the circuit section 2c, another normally open contact 11a2 of the relay 11, and a series circuit of the coil 21C of the relay 21 are connected in parallel. The lamp 22 is connected in parallel to the coil 21C. Since the earth leakage circuit breaker 1.2 is an automatic reset type, the normally open contacts 1ca and 2ca are closed when each earth leakage circuit breaker 1, 2 detects a zero-phase power supply above the threshold,
When it becomes less than this, it automatically returns to open circuit. Note that the circuit configurations of the branch feeder lines 43, 43, . . . are completely the same.

Before explaining the operation of this circuit, the logic judgment of this circuit will be explained.

In Table 1, 0/1 indicates that each of the earth leakage circuit breakers 1 and 2 is below/above the threshold value. If both the earth leakage circuit breakers 1 and 2 are "0" (1), there is naturally no earth leakage. Therefore, no-use breakers la and 2a do not operate.

If only the earth leakage circuit breaker 2 on the side of the branch feeder line 43 becomes ``1'''' (2), it is assumed that there is an erroneous detection of the transfer section, and the breakers la and 2a are not activated.

Conversely, earth leakage breaker 1 becomes “1” and earth leakage breaker 2 becomes “0”.
In the case (3), it is assumed that an earth leakage has occurred on the power source side than the earth leakage breaker 2, and the no-use breaker 1a is opened.

If both the earth leakage circuit breakers 1 and 2 are at "1 degree" (4), it is assumed that a current leak has occurred in the branch feeder line 43 provided with the earth leakage circuit breaker 2, and the no-use breaker 2a is opened.

The operation of the circuit will be explained below.

In case (1), contacts 1ca and 2ca are open, so coil I
Ic.

21C is demagnetized, contacts Lla, 21a are open, and coil 1aC of no-use breaker la, 2a.

2aC is not energized, so both breakers la, 2a
remains closed.

In case (2), the contact 2ca is opened due to the action of the circuit section 2c. However, in this case, the earth leakage breaker 1 does not detect a zero-sequence current higher than the dark value, so the contact 11az remains open, and the no-use breakers la and 2a both remain closed, as in the case (1). As described above, when an imbalance occurs at the transfer section, the zero-sequence current in the branch feeder lines 43, 43 on both sides becomes equal to or higher than the dark value, but none of the no-use breakers opens.

In case (3), the contact 1ca is closed by the action of the circuit portion 1c. As a result, the coil 11C is energized, the lamp 13 is turned on, and the timer section 12C of the time limit relay 12 starts measuring time. coil t
The contacts 11a++ 1laz are closed by the excitation of tc, and when the time limit relay 12 expires, the contact 12a is closed. When a leakage occurs in the main power supply line 42, the coil 1aC is energized as the contact 12a is closed, thereby opening the no-use breaker la. Since the earth leakage breaker 2 does not detect a zero-sequence current higher than the dark value, the contact 2ca remains open, and the no-use breaker 2a remains closed.

In the case of (4), on the earth leakage breaker 1 side, the coil I
The IC is excited and the time limit relay 12 starts timing. −
- Contact 2ca closes on the side of the earth leakage breaker 2.

Since the contact 11ag is closed by the excitation of the coil 11C, the coil 21C is energized and the lamp 22 is turned on. The contact 21a is closed by the excitation of the coil 21C, and the coil 2aC is excited. This opens the no-use breaker 2a. If there is a current leakage in the branch feeder line 43 disconnected by the no-use breaker 2a, the current detected by the zero-phase current transformer 1b becomes O because the leakage is disconnected. Then, since the earth leakage breaker 1 is an automatic reset type, contact 1c
a opens. In other words, since the contact 1ca opens before the contact 12a of the timer 12 closes, the no-use breaker 1a does not open, and power can be supplied to the other branch power supply lines 43 without any problem.

〔effect〕

The device according to the present invention as described above is capable of detecting current leakage ((4)
)), the no-use breaker will be opened correctly in the event of an earth leakage in the main power supply line (in the case of (3)), and the no-use breaker will be opened properly to protect the main power supply line from leakage (in the case of (3)). The breaker won't open either. Therefore, it goes without saying that the inconvenience caused by the presence of the transfer section is eliminated, and there is no need to provide a special position sensor to eliminate the problem, and the circuit is only a relay circuit, so regardless of the number of branch feeders, the timer 1
Since only one piece is required, modification can be done easily and economically.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of the earth leakage prevention device of the present invention, and FIG. 2 is a power supply system diagram for explaining the problem. 1.2...Earth leakage breaker 1a, lb...Zero phase current transformer la, 2a...No fuse breaker IL
21...Auxiliary relay 12...Time-limited relay patent Applicant: Tsubaki-shiki company Tsubakimoto Chain, agent Patent attorney: Noboru Kono (1 other person)

Claims (1)

[Claims] 1. A branch feeder line branched from a three-phase main feeder line equipped with an earth leakage breaker that detects earth leakage and interrupts the circuit using the zero-sequence current detected by a zero-phase current transformer, and a branch feeder line also equipped with an earth leakage breaker. In power supply equipment that supplies power to electric cars equipped with two sets of current collectors that can straddle the main feeder and come into contact with both branch feeders, the earth leakage circuit breaker of the main feeder is of an automatic reset type, and is activated by its operating contact. A time-limited relay and an energized auxiliary relay are provided, and the tripping coil of the earth leakage breaker is energized by the contact of the time-limited relay, and the operating contact of the earth leakage breaker of the branch power supply line and the contact of the auxiliary relay are provided. An earth leakage prevention device characterized in that the earth leakage prevention device is configured to excite a tripping coil of the earth leakage breaker.