JPH0728487B2 - Busbar insulation monitor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a busbar insulation monitoring device for monitoring the insulation state of a busbar of a switchgear such as a control center.

[Conventional technology]

FIG. 5 is a perspective view showing a conventional control center. The control center (1) comprises a housing (2) which houses a plurality of feeder units (3) for opening and closing a motor circuit and the like in a vertical direction and arranged horizontally in a row according to the number of feeders.

FIG. 6 is a diagram showing a power main circuit for one surface of the housing (2) of the control center (1) shown in FIG. 5, and FIG. 7 shows the housing (2) housing the feeder unit (3). It is a horizontal sectional view of a state. In FIG. 6, a main circuit power supply vertical bus bar (5) vertically lowered from a main circuit power supply horizontal bus bar (4) horizontally penetrating between adjacent boards is provided with a plurality of bus bar support devices (6) to form a housing (2). ) Insulated and supported. 6 and 7, the feeder unit (3) is inserted into the housing (2) so that the main circuit power supply vertical busbar (5) is formed in the main circuit disconnecting section (7).
It is automatically connected to and powered. Feeder unit (3)
Is a section breaker (9) connected to the main circuit disconnector (7) through the main circuit conductor (8), a section switch (10) connected in series with the section breaker (9), and a protection. It is composed of a device (11).

In FIG. 7, the sectional breaker (9) is opened / closed by operating the opening / closing handle (12) with the door (2a) on the housing (2) side closed.

Next, the operation of the above feeder unit (3) will be described. Closing / opening the sectional breaker (10) by operating the open / close handle (12) of the sectional breaker (9), closing the sectional breaker (9), and then operating the start / stop push button (not shown). Depending on the feeder unit (3)
The electric motor or the like of the load connected to is started / stopped. The overload of the load is detected by the protection device (11), and the section switch (10) is automatically opened. In the event of a short circuit in the load side circuit, the breaker (9) trips and interrupts the fault current.

In the control center configured as described above, a voltage is always applied to the main circuit power supply vertical bus bar (5), and insulation from the ground is maintained by the bus bar support device (6). Since the bus bar supporting device (6) is made of an insulating material (for example, glass polyester), it deteriorates with time,
Insulation resistance decreases. A decrease in insulation resistance causes a ground fault or a phase-to-phase short circuit, so it is necessary to measure the insulation resistance regularly in order to prevent an accident. For the measurement, the main circuit is cut off, that is, the application of voltage to the vertical bus bar (5) of the main circuit power supply is stopped, and then the feeder unit (3) is pulled out to block the influence on the insulation resistance given by the load side cable etc Then, measure the insulation resistance with a megger.

[Problems to be Solved by the Invention]

As described above, conventionally, the insulation deterioration of the busbar support device (6) of the control center needs to be periodically interrupted by a power failure, so that there is no choice but to stop the equipment to be continuously operated. there were. Further, there is a problem in that it is necessary to completely pull out the feeder unit (3) from the housing (2) for measuring the insulation resistance, which requires a great deal of labor.

The present invention has been made to solve the above problems, and it is possible to measure the insulation resistance of the bus bar supporting device (6) without requiring a power failure and without pulling out the feeder unit (3). An object is to provide a busbar insulation monitoring device.

[Means for Solving the Problems]

A busbar insulation monitoring device according to the present invention is a main circuit power supply busbar to which a main circuit voltage is applied and is insulated and supported from a housing by a busbar support device, and a dummy busbar having a cross-sectional shape substantially the same as the main circuit power supply busbar. A busbar supporting device for the dummy busbar which is made of the same member as the busbar supporting device and insulates and supports the dummy busbar from the housing; a switch connected between the main circuit power busbar and the dummy busbar; The resistance measuring terminal section is configured to open the insulation resistance measuring means to be connected to the bus of each phase of the dummy bus bar and the housing via the opening / closing means, and the switch at a predetermined time interval to open the circuit. After opening and closing the opening and closing means in a predetermined order, a control means for repeatedly executing a series of procedures for closing the switch is provided.

[Action]

The busbar supporting device for the dummy busbar according to the present invention is a target for measuring insulation resistance instead of the busbar supporting device for the main circuit power source busbar. The control means opens the switch at predetermined time intervals,
After the insulation resistance of the bus bar supporting device is measured by the insulation resistance measuring means, a series of operations of closing the switch again is repeatedly executed.

〔Example〕

FIG. 1 is a diagram showing a power main circuit for one surface of a casing (2) of a control center including a busbar insulation monitoring device (13) according to an embodiment of the present invention. The main circuit power supply vertical bus bar (5) vertically lowered from the main circuit power supply horizontal bus bar (4) horizontally penetrating between adjacent boards is provided with a plurality of bus bar support devices (6).
Is insulated and supported by the housing (2). The feeder unit (3) is automatically connected to the main circuit power supply vertical busbar (5) at the main circuit disconnecting section (7) by being inserted into the housing (2) and is supplied with power.

The feeder unit (3) is a sectional breaker (9) connected to the main circuit disconnector (7) via the main circuit conductor (8).
And a section switch (10) and a protection device (11) connected in series with the section breaker (9). A horizontal cross-sectional view of the feeder unit (3) housed in the housing (2) is similar to the conventional example and is shown in FIG. In FIG. 1, all units up to the fifth tier from the top of the casing (2) are feeder units (3), but the lowest unit is the busbar insulation monitoring unit (13). Like the feeder unit (3), this unit (13) is also provided with a main circuit disconnecting section (7), a main circuit conductor (8), a section breaker (9) and a section switch (10), The main circuit disconnector (7) is automatically connected to the main circuit power supply vertical busbar (5) by being inserted into the housing (2). The load side of the division switch (10) is connected to the dummy bus bar (14) by a main circuit conductor (33) made of, for example, a covered electric wire. FIG. 2 is a horizontal sectional view of the busbar insulation monitoring unit (13). The dummy bus bar (14) has the same horizontal cross-sectional shape as the main circuit power supply vertical bus bar (5) and is provided in the vertical direction like the main circuit power supply vertical bus bar (5), but its length in the vertical direction. Is very short as shown in FIG. The dummy bus bar (14) is insulated and supported by the housing (2) by the bus bar support device (15). This busbar support device (15)
Is the same component as the other busbar support device (6) and is made of, for example, glass polyester. As will be described later, the bus bar supporting device (15) is the other bus bar supporting device (6) as a measurement target for insulation resistance measurement. Since the external appearance of the busbar insulation monitoring unit (13) is similar to that of the feeder unit (3), the external appearance of the control center is substantially the same as that of the conventional example (Fig. 5).

FIG. 3 is an equivalent circuit diagram of the main circuit viewed from the busbar insulation monitoring unit (13). Three-phase main circuit power supply vertical bus (5a, 5b,
5c) shows the main circuit power supply vertical bus bar (5) of FIG. 1 in a three-phase circuit. Similarly, the main circuit disconnecting parts (7a, 7b, 7)
c) shows the main circuit disconnection part (7) of FIG. 1 in a three-phase circuit. Since the bus bar supporting device (6) in FIG. 1 has the ground insulation resistance (6a, 6b, 6c) and the interphase insulation resistance (6d, 6e), it can be expressed as shown in FIG. Similarly, the bus bar supporting device (15) of FIG. 1 also has insulation resistance to ground (15a, 15b,
15c) and interphase insulation resistance (15d, 15e), which are represented as in FIG.

In FIG. 1, in a normal operation state, a voltage is applied to the main circuit power supply horizontal bus bar (4) and the main circuit power supply vertical bus bar (5) to supply power to each feeder unit (3).

In Fig. 3, the insulation resistance to ground (6a, 6b, 6c) and the insulation resistance between phases (6d, 6e) are the main circuit power supply vertical buses (5a, 5b, 5c).
The voltage applied to is always applied to maintain insulation between the ground and the phases. On the other hand, the section breaker (9) and the section switch (10) of the busbar insulation monitoring unit (13) are normally closed, so insulation resistance to ground (15a, 15b, 15c) and insulation resistance between phases (15d, 15e) Similarly, the main circuit power supply vertical bus bar (5
The voltage applied to a, 5b, 5c) is applied. That is, the bus bar supporting device (6) and the bus bar supporting device (15) of the dummy bus bar (14) are electrically used under the same conditions. In terms of operating temperature, the higher the temperature inside the casing (2) is, the higher the temperature is due to heat generated by energization. Therefore, the busbar supporting device (6) provided on the upper side has a higher operating temperature. Conversely, the bottom busbar support (15) is used at the lowest temperature. In general, within the temperature difference range generated in such a housing (2), the insulator itself forming the bus bar supporting device (6 or 15) dries at a higher temperature, which is a favorable condition for maintaining the insulation performance. Becomes In other words, the bottom bus bar support (15) is used under the worst conditions. Further, since the dust is more likely to adhere to the lower part of the housing (2), the insulation performance is likely to be deteriorated. In this way, since the bus bar supporting device (15) of the dummy bus bar (14) is in worse use condition than any other bus bar supporting device (6), its insulation performance is regularly represented by the same bus bar supporting device (15). If it is measured, the measurement result will be a standard to know the deterioration of the insulation performance of all the bus bar supporting devices (6, 15).

FIG. 4 is a control circuit diagram of the busbar insulation monitoring unit (13). The busbar stop monitoring operation by the busbar insulation monitoring unit (13) will be described below. First, the circuit breaker (9) is manually closed. When the changeover switch (17) is switched from the state shown in the figure, a control voltage is applied from the main circuit power supply to the control circuit (13a). When the busbar insulation monitoring unit (13) is tested or the facility is out of service for a long period of time, the changeover switch (17) is switched to the state shown in the figure, and an external control power source is separately supplied from the external control power source terminal (32). The voltage circuit (13a) is protected by the fuse (18). Further, the short circuit accident in the main circuit portion after the section breaker (9) is protected by the section breaker (9).
By applying the suppression voltage, firstly, the sectional switch (10) is turned on via the timed return contact (22b) of the timer (22a), the open switch (20) and the contact (21b) of the time switch (21a) which are closed respectively. The electromagnetic coil (10a) of is excited,
The same category switch (10) is closed. As a result, the auxiliary contacts (10b) and (10d) of the division switch (10) are closed, and the self-holding of the division switch (10) and the red indicator light (24), respectively.
Lights up. The time switch (21a) is excited by the closing of the further auxiliary contact (10c) of the section switch (10), and the counting of time is started. After a certain time from the start,
The contact (21b) of the time switch (21a) is opened, and the electromagnetic coil (10a) of the section switch (10) is demagnetized. As a result, the green indicator light (25) lights up due to the closing of the auxiliary contact (10e) of the division switch (10). In addition, the division switch (1
0) Auxiliary contact (10c) open circuit timer (23a)
Is demagnetized. Since the contact (23b) of the timer (23a) is a contact that returns to the timed state after demagnetization, the timer (26a) is excited by closing the circuit after a fixed time period. When the timer (26a) is excited, its instantaneous contact (26b) is instantly closed to excite the timer (27a). When the timer (27a) is excited, its instantaneous contacts (27c, 27d) are instantly closed, and both ends of the resistance (15d) are connected to the measurement terminal (16b) of the insulation resistance meter (16). This insulation resistance meter (16) has the same function as, for example, a megger, and is supplied with power from the power input terminal (16a) and measures the resistance value of the resistor connected to the measurement terminal (16b). The signal corresponding to the measured value is output to the external output terminal (16
Output from c). Thus, firstly the interphase insulation resistance (15d)
A signal corresponding to the resistance value of is output from the external output terminal (16c). Next, after the elapse of a certain time period, the time-delayed operation contact (26c) of the timer (26a) is opened, and the timer (27a) is demagnetized. At the same time, the other time delay operation contact (26d) of the timer (26a) is closed, and the timer (28a) is excited. When the timer (28a) is excited, its instantaneous contact (28
b) closes and excites the timer (29a). When the timer (29a) is excited, its instantaneous contact (29c, 2
9d) is closed and the interphase insulation resistance (15e) is
6) connected to. Thus, a signal corresponding to the resistance value of the interphase insulation resistance (15e) is output from the external output terminal (16c). Next, after the elapse of a fixed time period, the time-delayed contact (28c) of the timer (28a) is opened, and the timer (29a) is demagnetized. At the same time, the other time-delayed contact (28a) of the timer (28a)
d) is closed and the timer (30a) is excited. When the timer (30a) is excited, its instantaneous contact (30b) closes,
Energize the timer (31a). The momentary contacts (31b, 31c, 31d, 31e) are closed due to the excitation of the timer (31a), and the insulation resistance (15a, 15b, 15c) to ground is paralleled in parallel with the three-phase insulation resistance meter (16). Connected to. In this way, a signal corresponding to the resistance value as a parallel body of the ground insulation resistances (15a, 15b, 15c) is output from the external output terminal (16c).
After a lapse of a certain period of time, the time-delayed operation contact (30c) of the timer (30a) is opened, the timer (31a) is demagnetized, and a series of insulation resistance measurement sequence operations is completed. Since the timed return contact (22b) of the timer (22a) is set to operate for a time period after the opening of the division switch (10) and before the end of the sequence operation described above, The switch (10) is closed again and the busbar support device (1
In 5), the normal voltage applied state is restored. Division switch (10)
The auxiliary contact (10c) is operated with the closing of the circuit, and the time switch (21a) and the timers (22a, 23a) are excited. In this way, the same sequence operation is repeated,
Insulation resistance is regularly measured. The measurement cycle is adjusted by the set time limit of the time switch (21a). If you want to measure the insulation resistance in a hurry while the time switch (21a) is set, you can open the sectional switch (10) by opening the open switch (20).
The same operation as the regular operation described above is performed, and the insulation resistance is measured.

In addition, in the above embodiment, the timer is used for the sequential measurement, but a sequential relay or the like may be used instead of the timer.

In addition, although the insulation resistance meter (16) is of the external output type in the above embodiment, a recorder may be built-in or a transmission device may be built-in to perform signal transmission.

Further, although the busbar insulation monitoring device according to the above-described embodiment is used for the control center, it is needless to say that the same can be applied to a busbar supporting device of another switchgear.

〔The invention's effect〕

As described above, according to the present invention, the insulation resistance of the bus bar supporting device for supporting the dummy bus bar connected to the main circuit power source bus bar through the partition switch is set by opening the partition switch at a predetermined time interval. Since it is configured to measure, there is an effect that the insulation resistance can be automatically measured even when the equipment is in operation. Further, by collecting the data measured periodically, it is possible to always grasp the change with time of the insulation performance of the bus bar supporting device, and it is possible to prevent accidents due to dielectric breakdown.

[Brief description of drawings]

FIG. 1 is a diagram showing a main circuit configuration of a control center including a busbar insulation monitoring apparatus according to an embodiment of the present invention.
The figure shows a horizontal cross-sectional view of the busbar insulation monitoring unit (13) in Fig. 1 housed in the housing (2) of the control center. Fig. 3 shows the busbar insulation monitoring unit (13) in the control center shown in Fig. 1. The equivalent circuit diagram of the main circuit seen, FIG. 4 is a circuit diagram showing the control circuit (13a) of the busbar insulation monitoring unit (13) and the main circuit portion after the section breaker (9), and FIG. FIG. 6 is a perspective view showing the outer shape of a control center, FIG. 6 is a view showing a main circuit configuration of a conventional control center, and FIG. 7 is a horizontal view showing a feeder unit (3) housed in a control center casing (2). FIG. 5 and 7 are drawings common to both the conventional example and the embodiment of the present invention. In the figure, (2) is a casing, (5, 5a, 5b, 5c) is a main circuit power supply vertical busbar, (6) is a busbar support device, (10) is a sectional switch, (14) is a dummy busbar, ( 15) is a bus bar support device, (15
a, 15b, 15c) insulation resistance to ground, (15d, 15e) insulation resistance between phases, (16) insulation resistance meter, (16b) measuring terminal, (21a)
Is a time switch, (22a, 23a, 26a, 27a, 28a, 29a, 30a, 31
a) is the timer, (27c, 27d) is the instantaneous contact of the timer (27a), (29c, 29d) is the instantaneous contact of the timer (29a), (31
b, 31c, 31d, 31e) are instantaneous contacts of the timer (31a). In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A main circuit power source bus bar to which a main circuit voltage is applied and is insulated and supported from a housing by a bus bar supporting device, a dummy bus bar having a cross-sectional shape substantially the same as the main circuit power source bus line, and the bus bar supporting device. A dummy busbar supporting device which is made of the same member as the above and which insulates and supports the dummy busbar from the housing, a switch connected between the main circuit power busbar and the dummy busbar, and an insulation resistance measuring terminal portion, The insulation resistance measuring means to be connected to the busbars of the respective phases of the dummy busbars and the housing via the opening / closing means and the switch are opened at a predetermined time interval, and the respective opening / closing means are opened in a predetermined order. A busbar insulation monitoring device comprising: a control unit that repeatedly executes a series of procedures for closing the switch after the switch is opened and closed.