JPH0219594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high voltage lightning arrester for a high voltage power transmission line.

[Conventional technology]

Conventionally, high-voltage power transmission lines have been equipped with lightning arresters, which consist of an air-gapped discharge tube and a ZnO-based varistor connected in series, between each line and the ground in order to protect the power line and the electrical equipment connected to it from lightning surges, etc. It is intervening.

For example, in Figure 2, one lightning arrester is installed on each line 10a, 10b, and 10c of an AC6600V high-voltage transmission line.
It shows a circuit diagram in which 1a, 11b, and 11c are connected. In this case, the voltage between each line and the ground is 6600V/√3, which is approximately 3800V, whereas the air gap type discharge tubes 12a, 12b, 12c with a discharge starting voltage of 5800V or more and the discharge starting voltage
ZnO varistors 13a, 13b, 1 of 5400V or higher
Lightning arresters 11a and 1 are connected in series with 3c, respectively.
1b and 11c are used.

[Problem that the invention seeks to solve]

When a lightning surge is applied to such a conventional power transmission line, depending on the amount of lightning energy, ZnO
The system varistor caused creeping discharge, which caused a follow-on current and caused destruction.

Furthermore, it was not possible to visually determine whether such a lightning arrester had been destroyed.

The present invention provides a device that has an appropriate follow-current interrupting function and also has a function of destroying the surge arrester itself before it destroys the surge arrester itself. In addition to preventing damage to the additional equipment, the damage to the additional equipment can be easily identified visually, and it is configured to be easily replaced.
The purpose of the present invention is to provide a high-voltage lightning arrester that facilitates functional recovery.

[Means for solving problems]

In order to achieve the above object, the present invention includes a surge arrester in which an air gap discharge tube and a ZnO varistor are connected in series to be attached to a high-voltage power transmission line, and a group of parallel micro gap discharge tubes corresponding to the discharge withstand capacity of the surge arrester. This is a high voltage lightning arrester characterized by being connected in series in a visible and replaceable manner.

The microgap type discharge tube is related to the disclosure by the present applicant (for example, JP-A-53-848), in which a conductive thin film is attached to the surface of an insulator, and a microgap of 10 to 100 μm is formed on this conductive thin film. death,
The conductive thin film is divided into multiple parts by this micro gap, electrodes are fixed to each of the conductive thin films at both ends of the divided parts, and conductive wires are electrically connected to each of the electrodes. A discharge tube that is covered with a coating material and filled with an inert gas such as Ar or Ne. This discharge tube has the characteristics of discharging at a relatively low voltage and of limiting leakage current to an extremely small value.

By connecting a large number of microgap discharge tubes in parallel, it is possible to create a desired surge resistance.

Figure 3 shows the results of measuring the surge resistance when microgap discharge tubes are connected in parallel.
This measurement was carried out using the current waveform generated by the (8×27) μsec current waveform generating circuit shown in FIG. Sample (microgap discharge tube)
was installed between b and d in Figure 4.

To determine whether the test was acceptable or not, impulses were applied five times to each of three samples for each current I and A, and the presence or absence of damage such as cracks in the glass or breakage of lead wires was confirmed. The application interval is 5 minutes. The sample used in the test had a discharge starting voltage of 300V±15% and a maximum current of 300mA lead wire diameter.
This is a 0.6mmφ microgap type discharge tube.

As is clear from FIG. 3, by connecting microgap type discharge tubes in parallel, the surge withstand capacity increases, and as the number of parallel connections increases, it becomes like a critical curve. Theoretically, if the discharge starting voltage is the same, the discharge and shunting will occur uniformly, so if the number of connections is N, the surge withstand capacity should be N times that of a single one. However, in reality, due to variations in the individual microgap type discharge tubes, the current is not uniformly divided, which places a burden on the microgap type discharge tubes, which have a quick response, and is thought to cause them to break down.

From FIG. 3, the number of microgap type discharge tubes required for the required surge resistance can be determined.

Next, as shown in Figure 1, in a circuit in which a device in which microgap type discharge tubes are connected in parallel is connected to a conventional lightning arrester, for example, if the follow current value that flows when the arrester breaks down is 5A, the microgap type discharge tube Since the maximum current value per one is 300 mA, follow-on current interruption is possible by connecting 17 in parallel. If the withstand capacity of the microgap discharge tube is exceeded, the microgap discharge tube will be destroyed. In this case, for example, as shown in Figure 5, something that looks like Figure a in its normal state will always be in open mode as shown in Figure B when it is destroyed, and it can be seen by visually observing the external appearance. damage can be easily identified.

Further, the microgap type discharge tube can be easily constructed to be easily replaced, and its function can be restored very easily.

[Effect]

Since the microgap type discharge tube blocks the follow-on current when the phase changes, by connecting it in series with a conventional arrester, destruction of the main body of the arrester due to the follow-on current can be prevented.

Furthermore, by connecting a large number of microgap discharge tubes in parallel, it is possible to support a discharge capacity of up to about 25,000A.

Furthermore, in the event of a surge that exceeds the withstand capacity, the surge arrester will be destroyed before the arrester itself, and the damage can be visually determined from its appearance, making it easy to replace.

〔Effect of the invention〕

The high-voltage arrester of the present invention prevents the main body of the high-voltage arrester from being destroyed, and even if the main body of the high-voltage arrester is destroyed, it remains in an open mode, so that a considerable number of power outages can be reduced. In addition, there is no need to measure with a conventional tester when replacing a broken micro-gap discharge tube, and it is possible to determine whether or not the micro-gap discharge tube is broken just by visually inspecting it. You can try to recover.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal sectional view of an embodiment of the present invention, and FIG.
The figure is a wiring diagram of a conventional lightning arrester, Figure 3 is a diagram of the surge withstand critical curve, Figure 4 is a test current waveform generation circuit, and Figure 5 is an explanatory diagram showing the states of a microgap discharge tube before and after destruction. . 1...Air gap type discharge tube, 2...ZnO varistor, 3...Micro gap type discharge tube, 4...
…insulator.

Claims (1)

[Claims] 1. A lightning arrester that is connected in series with an air-gapped discharge tube and a ZnO varistor is attached to a high-voltage power transmission line, and a large number of parallel micro-gapped discharge tube groups corresponding to the discharge capacity of the surge arrester are connected in series in a visible and replaceable manner. A high voltage lightning arrester characterized by being combined.