JPS5843963B2 - Soubun Limits Peigatabosenno Koshiyoukenshiyutsusouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a failure detection device for a phase-separated sealed busbar used in an electric power system.

Conventionally, the busbars of power generation and substations have been air-insulated, but in recent years, sealed gas-insulated power generation and substations have become widely used due to the reduction in site space and measures to prevent salt damage. .

However, the fault detection method for this sealed busbar is the same as the fault detection method for conventional air-insulated busbars. Although it is possible to detect and remove a fault inside the bus bar, it is not possible to detect which part of the bus bar is faulty, so it takes time to confirm the fault point and perform recovery operations. there were.

This point will be specifically explained using a conventional example.

FIG. 1 shows -fu of a phase-separated closed bus bar, in which a is a plan view and b is a side view.

As shown in Fig. 1, 1 is a busbar block, 2 is a busbar disconnector block, 3 is a CT block for line protection, 4 is a breaker block, 5 is a CT block for busbar protection, 6 is a line disconnector block, and 7 is a line disconnector block. These are drawer blocks, each covered with a metal case, and insulation between the block cases is provided by an insulating spacer 8.

The insulating spacer 8 insulates one bus bar from the case and maintains one bus bar. It prevents current from flowing through the case through the grounding point, and also insulates internal gas to prevent a failure from spreading to other parts. ing.

2B is a bus disconnector, 4B is a circuit breaker, 6B is a line disconnector, 3A is a primary conductor that connects the busbar disconnector 2B and breaker 4B, and 5A is a primary conductor that connects the breaker 4B and line breaker 6B. , these are supported by insulating spacers 8.

3B is CT for line protection, 5B is CT for busbar protection, IB
is a bushing for bow track.

Each of the blocks 1 to γ above, metal mounting pedestal IC, 2C
,4C.

It is installed on top of 6C, 7C, etc. and is grounded.

Although Fig. 1 shows only one phase of the two outgoing lines, the same applies to the other outgoing lines. It is composed of

Conventionally, a failure detection circuit as shown in FIG. 2 has been constructed for such a sealed bus bar.

That is, as shown in FIG. 2, a busbar protection differential relay 10 is provided to overlap the protection range of each outgoing line protection device 9, and a failure on the busbar side is detected from the busbar protection CT'5B.
The circuit breaker 4B was configured to open.

As a result, the busbar fault can be reliably removed, but since it is not possible to determine which block on the busbar side is faulty, in order to understand the accident, the busbar disconnector block 2 and track protection CT block 3 shown in FIG. , the breaker block 4, the CT block 5 for protecting the bus bar, etc., all had to be dismantled, and there was a drawback that the operation of all the lines had to be stopped during this time.

On the other hand, in the case of a relatively low-voltage bus, the protection method for a sealed busbar as described above and the "Shiyahei busbar protection method"
1 and shown in FIG. 3 may be adopted.

In FIG. 3, a is a partial side view and b is an equivalent electric circuit diagram of the portion shown in a.

For this purpose, the case of the bus block 1 is insulated and mounted on the pedestal 1C via the insulator 11, and the ground conductor 1
2 to ground at one point.

The current flowing through the ground conductor 12 is detected by the overcurrent detector 14 via the CT 13, and such equipment is provided for each block.

In the case of a phase-separated sealed busbar, if there is a busbar failure, it is always a one-wire ground fault between the busbar and the case, and if the case is grounded through the conductor 12, the fault current will always be reduced. The current flows through this conductor and reaches the ground, where it is detected by the CT 13i- and the overcurrent relay 14.

If this method is applied to each block shown in FIG. 1, the drawback of the conventional differential relay method shown in FIG. 2, which is that it is difficult to identify a faulty block, can be overcome.

However, with this method, the case of each block must be insulated from the ground, which increases cost and lowers reliability. Conventionally, high-voltage sealed buttons are used. It is not used as a busbar protection device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly reliable failure detection device that is capable of identifying failed blocks and that each block is firmly held.

Embodiments of the present invention will be described below based on the drawings.

FIG. 4 shows an embodiment of the present invention, in which a is a side view and b is a side view.
is an equivalent electric circuit diagram of the part shown in Figure a.

Although only a part of the busbar is shown in FIG. 4, the busbar case 1 includes a mounting frame 1C1 a mounting base 15 and a ground conductor 12.
The mounting base 15 and the grounding conductor 12 have relatively large insulation impedance.
The residue is embedded in a filling material 17 such as concrete or asphalt.

The current flowing through the ground conductor 12 is introduced into the overcurrent relay 14 via a current transformer 13 embedded in the filling material 11 or not embedded in the filling material 17.

The mounting base 15 of the mounting frame 1C1, the ground conductor 12, and the ground network 16 are made of conductors such as metal, and have extremely low impedance.

Such a fixed connection method is installed and peeled off for each block.

If there is a failure in the phase-separated sealed busbar, it is a failure between the busbar and the case, and as mentioned above, the filling material 17
The impedance of the mounting base 15p and the ground conductor 1 is
Since the impedance is much higher than that of the conductor 12, most of the ground current in the event of a fault flows through the conductor 12 and is detected by the current transformer 13 and the overcurrent relay 14.

Therefore, if a current transformer and an overcurrent relay are provided for each block divided by the insulating spacer 8, a faulty block can be detected.

However, the current transformer 13 of this method only needs to have a capacity that can operate the overcurrent relay even when saturated, and it is inexpensive because it does not need one with good characteristics like the conventional differential method. becomes.

If there is not a sufficient difference between the grounding impedance and the insulation impedance of the filling material, the block with the maximum output can be detected by comparing the secondary currents of the current transformers in each block. .

Furthermore, there is only one overcurrent relay, and
The sum of the secondary currents of each block OCT is manually operated to activate the protective relay, and each secondary current value of each block OCT is recorded on a recorder (demand meter, etc.) and used to determine a faulty block. It may also be a configuration.

As described above, in the present invention, the grounding circuit of the busbar case is buried in a filling material such as concrete or asphalt with relatively high insulating impedance, and the busbar case is directly held by the mount 1C, and the mount 1C is filled with a filling material such as concrete or asphalt. Since it is fixed with a material, the holding structure of the busbar case is strong, reliable, and easy to maintain.

It is of course possible to detect a faulty block.

[Brief explanation of the drawing]

FIG. 1 shows a phase-separated sealed generating bar, in which a is a plan view and b is a side view. FIG. 2 is a circuit diagram showing the circuit configuration of a conventional failure detection device. FIG. 3 shows another conventional failure detection device, in which a is a side view and b is an equivalent electrical circuit diagram of FIG. FIG. 4 shows an embodiment of the present invention, in which a is a side view and b is a side view.
is an equivalent electrical circuit diagram. In the figures, the same reference numerals indicate the same or equivalent parts. 1... Busbar block, 2... Busbar disconnector block, 3... CT block for line protection,
4... Breaker block, 5... CT 7" lock for bus bar protection, 6... Track disconnector block, γ... Drawer book, 8...1.
・Insulating spacer, 1 person...Bus bar, 3A. 5A...-Next conductor, 2B...Busbar disconnector, 4B...Line breaker, 6B...Line disconnector, 3B... CT for line protection, 5B...
... CT for bus bar protection, 7B ... Bushing for lead-out line, IC, 2C, 4C. 6C, 7C...Mounting frame, 9...Line protection device, 10...Differential relay for bus bar protection, 1
1...Insulator, 12...Grounding conductor, 1
3...Current transformer (CT), 14...Overcurrent relay, 15...Mounting base, 16...
...Grounding net, 17...Filling substance.

Claims (1)

[Claims] 1. A grounding conductor connected to a pedestal that directly supports the phase-separated sealed bus case in each insulated block, a current transformer that detects the current in the grounding conductor, and a pedestal that surrounds at least a portion of the grounding conductor. and a current detector for detecting the magnitude of the secondary current of the current transformer, wherein the impedance of the filling material is larger than the impedance of the grounding conductor. Fault detection device for busbars.