JPS6152106A - Controller for power system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a power system control device that performs various measurements, protection, and control using voltage introduced into the power system.

[Background of the invention]

A power system control device inputs line and bus voltage as one of its inputs, displays its magnitude, and provides a signal to synchronize the circuit breaker, or a signal to open the circuit breaker in the event of an accident. As a conventional method for introducing voltage into this control device, a voltage transformer (hereinafter referred to as a single KPT) has been used, but this is a large and expensive equipment. For this reason, there is a strong demand to omit the I'T, especially in low-voltage power systems. By the way, it is well known that voltage is input through PTt-, so please do not cite the source.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a power system control device that can control and protect an electric station without installing PTs such as lines as much as possible.

[Summary of the invention]

Electrical station equipment - Lightning arresters have traditionally been installed on railway lines to protect against lightning surges, but recently lightning arresters using zinc oxide elements, which have non-linear characteristics, have been increasingly installed. There is.

This zinc oxide lightning arrester (ZLA) is simply ZLA in structure.
Since the elements are connected in series and there is no series gap like in conventional lightning arresters, voltage is always applied to ZLA.

From the above, in the present invention, Z
LA is used as the line PT.

The equivalent circuit of ZLA is shown in FIG. 2, in which a resistor and a capacitor C are connected in parallel between the power transmission line and the ground. Therefore, the voltage across the equivalent resistor R30 can be taken out, and various controls that were conventionally controlled using the line FT voltage can be performed using this output, as in the past.

[Embodiments of the invention]

FIG. 3 shows an embodiment of the present invention. First, in this figure, A is the busbar, L is the transmission line, B is the breaker, and G is the line grounding switch. E is the control device of the present invention, and the bus side voltage (1) is the line side voltage Vt, obtained from the bus PT (or obtained from the bus PD).
is obtained from ZLA,D.

The intermediate potential vb of ZLAD installed on the rail is introduced into the control device ffEK. On the other hand, the bus voltage Vm is introduced from the bus PTF installed on the bus A to the control device fiE. By doing this, for example, it is possible to detect the absence of line voltage and turn off the line grounding switch G without installing the line PT. explain.

FIG. 1 shows the details of the control device E shown in FIG.
D1. In addition to connecting the voltage detection relay 1 that returns when the potential of LD2 disappears, connect the bus PTF and the υ lead-in line BD1.
．． A synchronization verification relay 2 is provided which compares the bus line voltage Vi drawn by BD2 and the line side voltage V+ introduced by ZLA and operates and outputs when they are in the same phase. Furthermore, a failure detection relay, for example, an undervoltage relay 3 is provided between the BDI and ED2 that are led in from the bus PTF.

The response of each of these detection relays is as follows. First, if there is no voltage on the line side, the LDI connected to ZLA and D
, LD2 disappears, the voltage detection relay 1 returns to its normal state and the normally open contact 11 of this relay closes. Under this condition, when the above-mentioned input command contact 4a and disconnection command contact 4b of the track grounding circuit G are closed, the closing coil GC and tripping coil GO of the track grounding switch G operate. It is possible to carry out the important functions of the track grounding switch G.

Second, when the synchronization verification relay 2 detects the synchronization between the two human power Vh and Vm and operates, this normally open contact 21 closes, so when the circuit breaker Bt- is closed, the closing command contact 5 of the separately provided closing command device By providing the contact point 21 in series with the contact point 21, it is possible to prevent the system from being added to the system asynchronously. B
C is the closing coil of breaker B.

Thirdly, the BDI drawn from the busbar PTF.

As the voltage of BD2 decreases, the undervoltage relay 3 returns as a system failure occurs, this contact 31 closes, and the timer 31T with an appropriate time limit is activated.
By closing the normally open contact 31Ta of the breaker B, an out-of-line command is given to the 4th outer coil BO of the breaker B to open the breaker t- and protect the power system. Although the relay 3 has been described here as an undervoltage relay, it goes without saying that it can be used for any relay that receives at least a voltage input.

As described above, the present invention introduces an intermediate potential between the lines ZLA and D, thereby omitting the line PT that was conventionally installed for introducing voltage on the line side, and significantly reducing the cost of the system. And by combining the bus side voltage drawn from bus I) T, ■ Important control of earthing circuit G ■ Synchronous verification for closing circuit breaker B ■ Detecting system failure and disconnecting circuit breaker B, etc. It is possible to realize so-called control and protection.

〔Effect of the invention〕

According to the present invention, since the line PT can be omitted, (1) there is no need to install the line FT, which was always required in the past, so costs can be significantly reduced in electrical stations with a large number of power transmission lines.

(2) The equipment installation space can be significantly reduced by omitting the line FT.

It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a detailed embodiment of the present invention, FIG. 2 is a diagram briefly explaining the outline of the present invention, and FIG. 3 is a diagram explaining a simplified embodiment of the present invention. D・;・Line zinc oxide lightning arrester (Line ZLA3, E...
Control device of the present invention.

Claims (1)

[Claims] 1. In a power system control device that introduces the bus voltage and line voltage of an electric station for measurement and protection, the voltage on the line side is obtained from the voltage between two points of a zinc oxide lightning arrester installed on the line. Control equipment for electric power systems.