CN110716075A

CN110716075A - Current transformer array switching circuit and control method

Info

Publication number: CN110716075A
Application number: CN201910959495.3A
Authority: CN
Inventors: 董立红; 符立梅; 赵振民
Original assignee: Xian University of Science and Technology
Current assignee: Xian University of Science and Technology
Priority date: 2019-10-10
Filing date: 2019-10-10
Publication date: 2020-01-21

Abstract

The invention belongs to the technical field of current transformer electricity, and relates to a current transformer array switching circuit and a method. The current transformer mutual inductance CT switching circuit comprises a plurality of current transformer mutual inductance CT switching circuits, wherein each current transformer mutual inductance CT switching circuit comprises a first current transformer end S1, a second current transformer end S2, a normally closed switch K1, a normally open switch K2 and a detection channel C1, the first current transformer end S1, the second current transformer end S2 and the normally closed switch K1 are connected in series to form a loop, one end of the normally open switch K2 is connected between the first current transformer end S1 and the normally closed switch K1, and the other end of the normally open switch K2 is connected with the detection channel C1. On the current transformer array, through the combination of electric switches, can realize the safe and reliable switching of transformer array, hardware detection channel that can also significantly reduce in addition has reduced the cost, has improved hardware utilization efficiency.

Description

Current transformer array switching circuit and control method

Technical Field

The invention belongs to the technical field of current transformer electricity, and relates to a current transformer array switching circuit and a control method.

Background

At present, in the field of medium-high voltage electricity, the electrical design of a current transformer is very critical in two points: the secondary side is ensured to be reliably grounded, and the purpose is to protect the safety of secondary side equipment and personnel; and secondly, the secondary side can not be opened, so that high-voltage discharge is prevented from being generated due to the open circuit of the secondary side, when the secondary side of the current transformer is opened, the secondary generates several kilovolts, and the high voltage can break down the insulation of the current transformer, so that the shell of the whole distribution equipment is electrified, and the electric shock of maintainers can be caused, thereby causing life danger. Therefore, the secondary side of the current transformer is generally not switchable because the switching process inevitably produces an instantaneous open circuit.

In the prior art, no effective solution exists regarding the switching of current transformers. This means that there are a corresponding number of detection channels for how many current transformers. When the number of current transformers is very large, the number of hardware detection channels may not be enough, and some device for switching the current transformers in turn is needed so as to share fewer detection channels.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a current transformer array switching circuit and a control method, even if the secondary side of a current transformer can be safely switched and the number of hardware detection channels is reduced.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: the utility model provides a current transformer array switching circuit, its characterized in that includes a plurality of mutual inductance CT switching circuit of electric current, mutual inductance CT switching circuit of electric current includes current transformer first end S1, current transformer second end S2, normally closed switch K1, normally open switch K2 and detection channel C1, current transformer first end S1 current transformer second end S2 and normally closed switch K1 establish ties and form a return circuit, normally open switch K2 one end is connected between current transformer first end S1 and normally closed switch K1, the normally open switch K2 other end meets with detection channel C1. The second terminal S2 of the current transformer is grounded, and the detection channel C1 is grounded.

The n current mutual inductance CT switching circuits are connected with the power supply through normally open switches K2 and K_2nAnd are connected in parallel to form a single-phase current transformer array, and the single-phase current transformer array is connected with a detection channel C1.

And the three single-phase current transformer arrays form a three-phase current transformer array.

A control method of a current transformer array switching circuit, applied to the circuit of any one of claims 1 to 3, comprising the steps of:

s1, when the current is not detected, the normally closed switch K1 is kept closed;

s2, when the current needs to be detected, the normally open switch K2 is firstly closed, a time is delayed for delta t, the S1 is ensured to be completely conducted with the detection channel C1, and then the normally closed switch K1 is opened;

and S2, when the detection channel needs to be disconnected after the detection is finished, resetting the normally closed switch K1, delaying for a period of time delta t, ensuring that the S1 and the S2 are completely short-circuited, and resetting the normally open switch K2.

In the single-phase current transformer array, the n current mutual inductance CT switching circuits are switched in turn, only one CT is connected into the detection channel C1 at a time, and the switching steps of each current mutual inductance CT switching circuit are the same as those of the method.

Each single-phase current transformer array in the three-phase current transformer array can be independently controlled.

Has the advantages that: the invention provides a current transformer array switching circuit and a control method, which can ensure that a secondary side of a current transformer is safely and reliably connected or disconnected with a detection channel. The method is applied to the current transformer array, and safe and reliable switching of the transformer array can be realized through the combination of the electric switches. By using the method, hardware detection channels can be greatly reduced, the cost is reduced, and the utilization efficiency of hardware is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a diagram of a current transformer switching method of the present invention;

FIG. 2 is a logic diagram for switching the current transformer according to the present invention;

FIG. 3 is a diagram of an array of single phase current transformers of the present invention;

fig. 4 is a three-phase current transformer array diagram of the present invention.

Detailed Description

To further explain the technical means and effects of the present invention adopted to achieve the predetermined object, the following detailed description of the embodiments, structures, features and effects according to the present invention will be given with reference to the accompanying drawings and preferred embodiments.

Example one

The utility model provides a current transformer array switching circuit, its characterized in that includes a plurality of mutual inductance CT switching circuit of electric current, as figure 1, mutual inductance CT switching circuit of electric current includes current transformer first end S1, current transformer second end S2, normally closed switch K1, normally open switch K2 and detection channel C1, current transformer first end S1, current transformer second end S2 and normally closed switch K1 establish ties and form a return circuit, normally open switch K2 one end is connected between current transformer first end S1 and normally closed switch K1, the normally open switch K2 other end meets with detection channel C1, current transformer second end S2 ground connection, detection channel C1 ground connection.

Fig. 2 is a control method of a current transformer array switching circuit, including the following steps:

Through the implementation of the circuit and the method, the secondary side of the current transformer can be safely and reliably connected or disconnected with the detection channel, the problem of potential safety hazards of the secondary side of the current transformer in the prior art is solved, and the safety of electrified equipment and maintenance personnel is ensured.

Example two

Referring to fig. 3, n current mutual inductance CT switching circuits are switched in turn, only one CT is connected to the detection channel C1 at a time, and the switching step of each current mutual inductance CT switching circuit is as described in claim 4.

The single-phase mutual inductor array shares one detection channel, each current mutual inductance CT switching circuit can realize the sequential switching in the single-phase mutual inductor array through the normally closed switch K1 and the normally open switch K2 according to the operation method in the first embodiment, and the hardware detection channels are greatly reduced by using the circuit and the method, and the circuit and the method are safe and reliable. The electric switch can be controlled to be switched on or switched off by programmable devices such as a PLC (programmable logic controller), an industrial personal computer and the like, so that the control is more convenient.

EXAMPLE III

Fig. 4 shows the switching principle of a three-phase current transformer array. The signal detection of the three-phase current transformer array needs three detection channels C1-C2-C3 which respectively correspond to three phases A-B-C. The current transformer switching and detection principle is fully consistent with fig. 3 for each phase.

The difference is that in order to ensure that the three-phase ABC of the same group is detected and disconnected simultaneously, KA1-KB1-KC1 is triggered by the same control signal to achieve the linkage effect, and similarly, KA2-KB2-KC2 is triggered by the same control signal, and the like. That is, three switches in each horizontal direction in fig. 4 are synchronously triggered, so that the simultaneity of three-phase detection is ensured.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The utility model provides a current transformer array switching circuit, its characterized in that includes a plurality of mutual inductance CT switching circuit of electric current, mutual inductance CT switching circuit of electric current includes current transformer first end S1, current transformer second end S2, normally closed switch K1, normally open switch K2 and detection passageway C1, current transformer first end S1, current transformer second end S2 and normally closed switch K1 establish ties and form a return circuit, normally open switch K2 one end is connected between current transformer first end S1 and normally closed switch K1, the normally open switch K2 other end meets with detection passageway C1, current transformer second end S2 ground connection, detection passageway C1 ground connection.

2. The current transformer array switching circuit of claim 1, wherein n of said current transformer CT switching circuits are switched by normally open switches K2 and K_2nAnd are connected in parallel to form a single-phase current transformer array, and the single-phase current transformer array is connected with a detection channel C1.

3. The current transformer array switching circuit of claim 1, wherein three of said single phase current transformer arrays comprise a three phase current transformer array.

4. A control method of a current transformer array switching circuit, applied to the circuit of any one of claims 1 to 3, comprising the steps of:

5. A control method of a current transformer array switching circuit, which is applied to the circuit of any one of claims 1 to 3, wherein in the single-phase current transformer array, n current mutual inductance CT switching circuits are switched in turn, only one CT access detection channel C1 is available at a time, and the switching steps of each current mutual inductance CT switching circuit are as in claim 4.

6. A method of controlling a switching circuit of a current transformer array applied to a circuit according to any one of claims 1 to 3, wherein each single-phase current transformer array of the three-phase current transformer array is individually controllable.