KR820001622Y1 - Lighting arrester device for power transmission line - Google Patents

Abstract

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Description

Lightning arrester for transmission line

1 is an explanatory diagram showing an application example of a conventional lightning arrester for a transmission line.

2 is a block diagram showing an equivalent circuit of an embodiment of the present invention.

3 is an external view of the configuration of FIG. 2 applied to a transmission line.

FIG. 4 is a cross-sectional view showing broken lines in FIG. 3.

FIG. 5 is an explanatory diagram showing a state in which a soluble line is melted.

* Explanation of symbols for main parts of the drawings

(1): lightning arrester (2): reactor

(3): gap (5): soluble ship

(9): transmission line (23): steel tower

The present invention relates to a transmission line lightning arrester that can be jointed at the time of failure applied to the transmission line.

Transmission lines are generally provided with overhead lines and shield the lightning strikes on the transmission lines. However, when the lightning current becomes large, the potential of the steel tower, which is usually the ground potential, rises, and this voltage rises opposite to the grid voltage of the transmission line, so that a so-called reverse flashover occurs. For this reason, since the system is in a ground state and a ground current flows, a system in which a ground current is interrupted by a circuit breaker in the system and then re-input is adopted.

Recently, in power transmission lines requiring high voltage and large capacity, the limit of power transmission capacity depends on the transient stability of the system at the time of interruption and reentry.

In order to improve the transient stability, it is necessary to prevent the reverse flashover from occurring, and a method of installing a lightning arrester in a transmission line has been studied.

Conventional lightning arresters have a structure in which special elements made of series gaps and silicon carbide (Sic) are connected in series, as is well known. Since the stray capacitance of the series gap is a small value of about 18PF, the discharge characteristic of the gap tends to be changed by ambient conditions, for example, a fouling state of the insulator surface accommodating the lightning arrester. I needed a guarantee. In addition, if the characteristic element of silicon carbide is used, several hundreds of currents flow due to normal ground voltage, so that it is not a complete ground fault removal measure. Application has not reached the practical level.

Recently, a high temperature sintering element (referred to as ZnO element) consisting of a small amount of additives such as bismuth (Bi), antimony, cobalt, etc. has been developed with zinc oxide (ZoO) as a main component. It became.

The ZnO element is very excellent in non-linearity of voltage-current characteristics, and it is possible to fabricate a lightning arrestor having a current flowing at a normal ground voltage of about several tens of microamperes, that is, a leakage current of an insulator. This eliminates the series gap required by conventional models. It can be covered by the application of the conventional lightning arrester described above.

That is, in the normal ground voltage, it does not flow hundreds of amperes of current as in the conventional type, and it can be said that it is a non-current, so only the pulse of the lightning current responds, so that no disturbance is given to the system at all. Moreover, since there is no series gap like a conventional type, stable performance is obtained regardless of external environmental conditions. However, even in such an ideal lightning arrester, since it absorbs the abnormal voltage caused by the thunderbolt phenomenon, although there is a low probability, there may be a case where the arrester processes a current having a value higher than the assumed lightning current. In this case, there is a fear that the ZnO element inside the lightning arrester is destroyed. If the ZnO element is destroyed, the terminals between the arrester terminals are in a normal state, and a ground fault current flows due to the normal ground voltage. In such an abnormal state, it is necessary to quickly remove the lightning arrester for the transmission line from the system.

As shown in FIG. 1, the transmission line 9 is supported by the pylon 23 through the suspension insulator 10, and the lightning arrester 1 having one end connected to the pylon 23 is available. It is connected to the power transmission line 9 via a line 5.

In general, the soluble wire 5 is used for jointing in the case of a failure of the transmission line lightning arrester 1, but the soluble wire is not melted by the lightning current, and the size of the soluble wire that is melted by the ground fault current at the time of failure is selected.

The lightning current handled by the transmission arrester is generally 100KA to 150KA, and has a wave length of about 2 µS and a wave length of about 70 µ as a waveform. On the other hand, the ground fault current that flows during the arrester failure depends on the system and is about 200A to 50KA. If we assume that the ground current of 200A lasts for 0.1 second, this energy is less than the lightning current 100KA.

Therefore, there is a drawback that the soluble wire is melted by the energization of the lightning current, and the joint function cannot be exerted.

The present invention connects a lightning arrester, a reactor, and an available line in series, connects a gap in parallel with a reactor and an available line contacted in series, and connects a transmission line and a ground, ie, a steel tower, so that a lightning strike pulse passes through the gap. The ground fault current is configured to flow through the reactor via the reactor, and provides a lightning arrester for the transmission line that can cut the arrester from the transmission line by melting of the available line.

Next, it demonstrates based on drawing. In FIGS. 2-4, the joint part which consists of a gap part 4 comprised by the lightning arrester 1, the reactor 2, and the gap 3, the fusible line 5, and a disconnection part ( 7) is connected as shown in FIG. 2, and is connected to the power transmission line 9 through the connecting bracket 8 as shown in FIG. In addition, the power transmission line 9 is separately supported by the suspension insulator 10. 2, an equivalent circuit is used for the arrester 1 and the suspension insulator 10 as capacitance.

Figure 4 shows a specific embodiment of the present invention. The arrester 1 is configured by storing the ZnO element 12 inside the insulator 11. The gap part 4 consists of the gap 3 which consists of the flange 13 which shares the lid of the arrester 1, the electrode 14, the reactor 2, and the insulating cylinder 15 which accommodates these.

The reactor 2 and the electrode 14 penetrate through the insulating disc 16 and are connected to the cutout part 7, the soluble wire 5, and the disconnecting part 6, respectively.

The cutting part 7 is comprised from the soluble wire 5 and the disconnection part 6, and the insulating cylinder 17 which accommodates these. The disconnecting portion 6 includes a compression spring 18 and a stop plate 21 and a bolt (for use for fixing the shunt 19 and the compression spring 18 to the flange 20 for the purpose of energization). 22).

As described above, the arrester 1 is normally electrically connected with the reactor 2 and the available line 5 in series between the pylon 23 and the power transmission line 9.

Next, the operation will be described. 2 to 4, when the arrester 1 operates with a lightning impulse, the impedance of the reactor 2 increases because the frequency is high, and the lightning current does not flow through the available line 5, but the voltage in the gap 3 is increased. Will be applied. Therefore, the lightning impulse current flows through the gap 3 and the shunt 19 to the splice fitting 8. On the other hand, when the arrester is in an abnormal state, a ground fault current of the commercial frequency flows, but because the frequency is too low, the impedance of the reactor 2 is sufficiently low, and therefore the ground fault current flows through the reactor 2 through the reactor line 5. . When the soluble wire 5 is cut off by a ground fault current, an arc occurs in this part, and the pressure of the space 23 in the insulating cylinder 17 of the cutout 7 rises.

If the volume of the space 23 is made small enough, a pressure rise of 10 atm or more is expected. By breaking the insulating cylinder 17 by this increase in pressure resistance, the arrester 1 can be quickly cut off from the power transmission line 9. 5 shows the situation when the joint 7 performs a joint operation.

According to the present invention, a lightning arrester, a reactor, and a soluble wire are connected in series, and a gap is connected in parallel with the reactor and the soluble wire, whereby a lightning impulse flows through the gap, and a ground fault current flows through the soluble wire. The available line is bleeding, so that the arrester can be quickly dismantled from the transmission line.

In addition, the arrester can be cut off from the power transmission line when the soluble wire is melted by configuring the second insulating cylinder containing the soluble wire so as to break due to the pressure rise caused by the arc generated at the time of melting of the soluble wire.

Claims (1)

The lightning arrester 1, the reactor 2, and the soluble wire 5, which are composed of a sintered body mainly composed of zinc oxide or the like, are connected in series, and the reactor 2 and the soluble wire connected in series are connected ( 5) A lightning arrester for a transmission line, comprising a gap (3) connected in parallel to the transmission line and connected between the power transmission line (9) and ground.