CN213602410U

CN213602410U - Passive trigger of fault current limiter

Info

Publication number: CN213602410U
Application number: CN202022099530.XU
Authority: CN
Inventors: 杨盼峰; 毛凤麟
Original assignee: Xi'an Ancient River Electrical Engineering Co ltd
Current assignee: Xi'an Ancient River Electrical Engineering Co ltd
Priority date: 2020-09-23
Filing date: 2020-09-23
Publication date: 2021-07-02
Anticipated expiration: 2030-09-23

Abstract

The utility model relates to a passive trigger of fault current limiter, the quick trigger of mainly used sending out, power supply system fault current limiter starts. Two branches are connected in parallel at two ends of a secondary side winding of a current transformer connected with a main diversion loop: one branch is a secondary resistor, and the other branch is formed by connecting a pressure-sensitive device and an electric detonator in series. When the power generation and supply system is in short circuit, the voltage on the secondary resistor of the current transformer is larger than the threshold value of the pressure sensitive device, the pressure sensitive device is conducted, the electric detonator is rapidly detonated, and the purpose of rapidly and controllably detonating the electric detonator by utilizing the self energy of the short-circuit current is achieved. The utility model has the advantages that: the trigger does not use an active electronic chip inside, and has simple structure and reliable action.

Description

Passive trigger of fault current limiter

Technical Field

The utility model relates to a power electronic technology field specifically is a fault current limiter passive trigger, and the quick trigger of mainly used send out, power supply system's fault current limiter starts.

Background

When a short-circuit fault occurs in a power generation and supply system, a high-amplitude short-circuit current is generated. In order to guarantee safe power supply, a fault current limiter (short for current limiter or FCL) is needed. There are many principles and types of restrictors, among which the blasting cutting type restrictors are most widely used in domestic and foreign markets. The Chinese patent with the patent number of 200820028343.9, namely a high-current high-speed switch, is the core component of the current limiter. The high-speed switch uses miniature explosive as energy source and is detonated by miniature electric detonators. Therefore, an active electronic system consisting of a large-current sensor, an electronic controller, a pulse transformer and the like is required to trigger and control the large-current sensor. As a result, the structure is complicated, the number of electronic components is large, and the reliability of the device is lowered.

Therefore, chinese patent No. 201220710617.9, entitled "a high current passive trigger", proposes a trigger without active chip, in which a shunt is connected in series in the short circuit current loop, and when a short circuit fault occurs, the short circuit current shunted by the shunt is used to directly detonate the electric detonator, triggering the high speed switch and the current limiter to operate. The structure is simplified, and the reliability of the device is improved. But the disadvantages of the proposal are that: (1) the shunt is directly connected in series in the main power supply loop, has the problem of heating and needs to bear the test of thermal stability of long-term working current of about 1kA-6.3 kA; (2) the shunt also needs to meet the dynamic stability test of passing tens of kiloamperes of short-circuit current, so the selection and the manufacture of the shunt can be difficult.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is overcome in the background art not enough, provide a simple structure that need not active electronic chip, can set for the passive trigger of fault current limiter of starting value.

The technical scheme of the utility model is that: a fault current limiter passive trigger comprises a current transformer and a pressure-sensitive device, and is characterized in that: the current transformer is connected in series in a main loop, and two branches are connected in parallel on a secondary winding of the current transformer: one branch is a secondary resistor, and the other branch is formed by connecting a pressure-sensitive device and an electric detonator in series.

The secondary resistor and the pressure-sensitive device are arranged in a shielding box, and the shielding box and the current transformer are relatively fixed.

Further, the electric detonator is led out through an electrode lead.

Further, the electric detonator is extended to a blasting switch arranged on one side of the current transformer through an electrode lead wire; the explosion switch is provided with an explosion fracture.

Further, the electric detonator is specifically extended to an explosion fracture of an explosion switch arranged on one side of the current transformer through an electrode lead.

Preferably, the current transformer is a feedthrough transformer or a transformer with a primary winding.

Compared with the prior art, the utility model discloses produced positive effect is:

(1) the current-guiding row of the power supply loop is just a primary winding of the current transformer, so that the problem of long-term heating (thermal stability) and the problem of dynamic stability which needs to be specially solved under the condition of short circuit do not exist;

(2) the problem of a high-voltage power supply for supplying power to the electronic chip is not considered due to the absence of an active chip;

(3) the starting value is controllable: under normal conditions, the voltage drop of the secondary resistor is smaller than the threshold value of the pressure-sensitive device, and the pressure-sensitive device is not conducted; and only when short-circuit fault occurs, the voltage drop of the secondary resistor is greater than the threshold value of the pressure sensitive device, and the triggering branch circuit can be conducted to trigger the electric detonator to detonate. Thus, by changing the resistance of the secondary resistor and the threshold of the pressure sensitive device, the start-up value can be changed.

(4) The structure is simplified, the cost is reduced, and the reliability is improved.

Drawings

Fig. 1 is a schematic structural view of a first embodiment of the present invention;

fig. 2 is a schematic structural view of a second embodiment of the present invention;

in the figure: 1-high voltage diversion loop, 2-current transformer, 3-secondary side winding, 31-primary winding, 4-secondary resistor, 5-pressure sensitive device, 6-electric detonator, 7-shielding box, 8-electrode lead, 9-blasting switch, 10-blasting fracture.

Detailed Description

In order to make the technical solution of the present invention better understood by those skilled in the art, the present invention will be further described with reference to the following specific embodiments, which are provided as illustration only and are not intended to limit the present invention.

Fig. 1 shows the structure diagram of the first embodiment of the present invention, which is mainly to access the current transformer 2 in the high voltage diversion loop 1, and two branches are connected in parallel at two ends of the secondary winding 3 of the current transformer 2: one branch is composed of a secondary resistor 4, and the other branch is composed of a pressure sensitive device 5 and an electric detonator 6 which are connected in series. The secondary resistor 4 and the pressure sensitive device 5 are arranged in a shielding box 7, the shielding box 7 and the current transformer 2 are relatively fixed, and the electric detonator 6 is led to an explosion fracture 10 of an explosion switch 9 through an electrode lead 8.

The operation process of the device is illustrated by taking fig. 1 as an example: let the resistance of the secondary resistor 4 be R1, the resistance of the electric detonator 3 be R2, and the transformation ratio of the current transformer 2 be k. Under the condition of normal operation, the load current of the main loop is i1, and the voltage U1 on the secondary resistor 4 is approximately equal to (i1/k) R1; under the condition that the voltage-sensitive device 5 adopts a bidirectional TVS, the clamping voltage is Ut, and the load current i1 is smaller under the normal condition, so that the U1 is less than Ut, the TVS cannot be conducted, no current flows in the detonator 6, and the detonator cannot be detonated; when short-circuit fault occurs, the short-circuit current ik is increased to be more than ten times of the load current i1, the voltage U2 ≈ (ik/k) R1 > Ut on the secondary resistor 4, and the TVS of the voltage-sensitive device 5 is changed from locking to conduction; the secondary current mainly flows through the pressure sensitive device 5(TVS) and the detonator 6, and under the action of the secondary current, the detonator 6 is rapidly detonated, and then the explosion fracture 10 of the explosion switch 9 is triggered to act, so that the passage of the short-circuit current is rapidly cut off, and the rapid protection effect is achieved.

Since the transformation ratio k of the current transformer 2, the resistance value R2 of the secondary resistor 4 and the clamping voltage Ut of the voltage-sensitive device 5(TVS) are all selectable, the trigger can be started when the short-circuit current reaches a certain required value by selecting appropriate parameters, so that the starting value can be set. Therefore, the purposes of quickly and controllably detonating the detonator and triggering the action of the blasting switch by utilizing the self energy of the short-circuit current are achieved.

Fig. 2 shows a schematic structural diagram of a second embodiment of the present invention, and the main difference from fig. 1 is that the current transformer 2 is not a feedthrough transformer, but a transformer having a primary winding. The primary winding 31 of the current transformer 2 is connected in series in the high-voltage diversion loop 1, and the other parts are the same as those in fig. 1, and the principle and the calculation formula are also the same.

The present invention is not described in detail in the prior art.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fault current limiter passive trigger, characterized by: a current transformer (2) is connected into a high-voltage diversion loop (1), two branches are connected in parallel at two ends of a secondary side winding (3) of the current transformer (2), one branch is a secondary resistor (4), and the other branch is formed by connecting a pressure-sensitive device (5) and an electric detonator (6) in series.

2. A fault current limiter passive trigger as claimed in claim 1 wherein: the secondary resistor (4) and the pressure-sensitive device (5) are arranged in a shielding box (7), and the shielding box (7) and the current transformer (2) are relatively fixed.

3. A fault current limiter passive trigger as claimed in claim 1 wherein: the electric detonator (6) is led out through an electrode lead (8).

4. A fault current limiter passive trigger as claimed in claim 3 wherein: the electric detonator (6) is extended to the blasting switch (9) arranged on one side of the current transformer (2) through an electrode lead (8).

5. A fault current limiter passive trigger as claimed in claim 4 wherein: the explosion switch (9) is provided with an explosion fracture (10).

6. A fault current limiter passive trigger as claimed in claim 4 wherein: the electric detonator (6) is specifically extended to an explosion fracture (10) of an explosion switch (9) arranged on one side of the current transformer (2) through an electrode lead (8).

7. A fault current limiter passive trigger as claimed in claim 1 wherein: the current transformer (2) is a straight-through transformer or a transformer with a primary winding (31).