CN203039359U - Starting device of transformer low-voltage side high-speed short-circuit current limiter - Google Patents

Abstract

The utility model discloses a starting device for a high-speed short-circuit current limiter at the low-voltage side of a transformer, which solves the problem that the current-limiting reactor sometimes cannot be normally put into operation caused by the unreasonable structure of the existing device. The fast isolator (4) is connected in parallel with the special current-limiting fuse (5) and then connected in series in the high-voltage bus (1), and the current change rate sensor (2) is set on the high-voltage bus (1), and the current change rate sensor ( 2) It is electrically connected to the input terminal of the first electronic controller (3), and the output terminal of the first electronic controller (3) is electrically connected to the control input terminal of the fast isolator (4). A current sensor (6) is provided, the current sensor (6) is electrically connected to the input end of the second electronic controller (7), and the output end of the second electronic controller (7) is connected to the control input end of the fast isolator (4) electrical connection. The utility model provides a more reliable starting means for the starting of the existing high-speed short-circuit current limiter.

Description

A starting device for a high-speed short-circuit current limiter on the low-voltage side of a transformer

technical field

The utility model relates to a starting device for a high-speed short-circuit current limiter fuse on the low-voltage side of a transformer.

Background technique

Transformers are the most important equipment for power grid transmission. In recent years, with the rapid growth of electricity load, the short-circuit current of local grids has reached a very high level, and it is necessary to use current-limiting reactors to limit the short-circuit current of these nodes. The short-circuit current limiter is composed of fast isolator, special high-voltage current-limiting fuse, current sensor, electronic controller, high-voltage isolation transformer and other components. The fast isolator and the special high-voltage current-limiting fuse are electrically connected in parallel. Since the former has a micro-ohm resistance and the latter has a milliohm resistance, almost all the bus current flows through the fast isolator during normal operation. When a short-circuit fault occurs in the system, the current change rate sensor placed inside the fast isolator transmits the short-circuit current signal in the busbar to the high-voltage side electronic controller through the signal cable, and the high-voltage side electronic controller analyzes and processes the signal. If the short-circuit current signal exceeds the set value, the electronic controller on the high-voltage side will output an ignition pulse signal through the signal cable, so that the actuator in the fast isolator, that is, the blasting cutting system, will act, and the conductive circuit of the isolator will be disconnected at high speed within hundreds of microseconds. ; During the disconnection of the conductive circuit of the isolator, the fault current is transferred to the special high-voltage current-limiting fuse, and the special high-voltage current-limiting fuse finally breaks the short-circuit current and removes the fault. The starting link of this structure sets two starting criteria of current instantaneous value and instantaneous rate of change. Only when the two criteria are satisfied at the same time, can the actuator in the fast isolator start to ignite. In this way, under some operating conditions of the line, if the local insulation of the busbar is not completely damaged instantaneously, but the insulation is gradually reduced, although the instantaneous value of the current has reached the ignition condition, due to the gradual increase of the short-circuit current, the instantaneous change rate of the current in the start-up link It will not be able to meet the ignition conditions, and finally lead to serious short-circuit faults on the line, and the current-limiting reactor cannot be normally put into operation, which makes the transformer withstand a large short-circuit current for a long time, and poses a greater threat to the safe operation of the transformer.

Contents of the invention

The utility model provides a starting device for a high-speed short-circuit current limiter on the low-voltage side of a transformer, which solves the problem that the current-limiting reactor sometimes cannot be put into work normally due to the unreasonable structure of the starting device of the high-speed short-circuit current limiter on the low-voltage side of the transformer. , leading to technical problems of severe short circuit faults in the line.

The utility model solves the above problems through the following solutions:

A starting device for a high-speed short-circuit current limiter on the low-voltage side of a transformer, including a high-voltage bus, a fast isolator and a special current-limiting fuse connected in series in the high-voltage bus, and a current change rate sensor is arranged on the high-voltage bus. The sensor is electrically connected to the input end of the first electronic controller, the output end of the first electronic controller is electrically connected to the control input end of the fast isolator, and a current sensor is also arranged on the high-voltage bus, and the current sensor is connected to the second electronic controller The input end of the second electronic controller is electrically connected to the control input end of the fast isolator.

The ignition signal output by the output terminal of the first electronic controller is a pulse signal.

The utility model adds a new starting function to the existing high-speed short-circuit current limiter fuse starting device, provides a more reliable starting means for the starting of the existing high-speed short-circuit current limiter, and avoids serious short-circuit faults of the line.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

A starting device for a high-speed short-circuit current limiter on the low-voltage side of a transformer, including a high-voltage bus 1, a fast isolator 4 and a special current-limiting fuse 5 connected in parallel to the high-voltage bus 1, and a current change rate is set on the high-voltage bus 1 The sensor 2, the current change rate sensor 2 is electrically connected to the input terminal of the first electronic controller 3, the output terminal of the first electronic controller 3 is electrically connected to the control input terminal of the fast isolator 4, and the high voltage bus 1 is also provided with The current sensor 6 is electrically connected to the input end of the second electronic controller 7 , and the output end of the second electronic controller 7 is electrically connected to the control input end of the fast isolator 4 . The current in the high-voltage bus 1 is I.

The ignition signal output by the output end of the first electronic controller 3 is a pulse signal.

The concrete implementation of the present utility model can pass through the following steps:

The first step is to add a group of Rogowski coil current sensors, namely the current sensor 6 and the existing current change rate sensor 2, to the high-voltage busbar and connect them in the current loop of normal operation;

In the second step, a second electronic controller 7 is added in the control loop, and the current signal of the current sensor 6 added in the first step is introduced into the controller, and its power supply can be shared with the power supply of the original first electronic controller 3 ;

In the third step, the output of the newly added second electronic controller 7 is connected in parallel with the output contact of the ignition system of the original first electronic controller 3;

In the fourth step, the current setting value and time limit in the newly added second electronic controller 7 can cooperate with the current protection on the low-voltage side of the transformer.

The utility model inputs the current signal of the current sensor 6 into the second electronic controller 7, uses the built-in program to quickly calculate the effective value of the current, and judges whether to output the ignition signal according to the set value. When the local insulation of the high-voltage bus 1 is not completely damaged instantly, but the insulation is gradually reduced and the short-circuit current is gradually increased, although the instantaneous value of the current has reached the ignition condition, the instantaneous change rate of the current may not meet the ignition condition, resulting in limited When the current-limiting reactor cannot be reliably switched on, if both the instantaneous current value and the current effective value can meet the ignition conditions, the ignition will be started after a certain time limit, so that the current-limiting reactor can be reliably switched on, and the transformer will not be subjected to large loads for a long time. Short-circuit current ensures the safe operation of the transformer.

Claims (2)

1. the starting drive of a step down side high speed short circuit current limiter, comprise high voltage bus (1), fast isolator (4) be serially connected in the high voltage bus (1) after extraordinary current limiting fuse (5) is in parallel, it is characterized in that, high voltage bus (1) is provided with current changing rate transducer (2), current changing rate transducer (2) is electrically connected with the input of first electronic controller (3), the output of first electronic controller (3) is electrically connected with the control input end of quick isolator (4), on high voltage bus (1), also be provided with current sensor (6), current sensor (6) is electrically connected with the input of second electronic controller (7), and the output of second electronic controller (7) is electrically connected with the control input end of quick isolator (4).

2. the starting drive of a kind of step down side high speed short circuit current limiter according to claim 1 is characterized in that, the ignition signal of the output output of first electronic controller (3) is pulse signal.

Images