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Open-circuit protection device and method for secondary circuit of current transformer

A technology of current transformer and secondary circuit

Pending Publication Date: 2021-01-01
国网四川省电力公司遂宁供电公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the current transformer is in normal operation, its secondary side load impedance is small, similar to a short circuit state, and the secondary voltage is low; when the secondary circuit is open, the current transformer is very easy to enter the electromagnetic saturation state, and the secondary side will induce High voltage (up to 10,000 volts) can burn adjacent secondary equipment, and at the same time cause primary equipment to heat up, burn down or even explode
According to accident reports in the power industry, it is not uncommon for current transformers to have secondary circuit open circuit accidents, which often lead to heavy losses and seriously threaten the safety of people, power grids and equipment
[0003] At present, the existing current transformer protection device is directly connected in series to the secondary circuit. Although it can protect the circuit when an open circuit fault occurs in the secondary circuit of the current transformer, it will bring certain problems when the secondary circuit works normally. loss of power dissipation, and additional risk of an open circuit

Method used

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  • Open-circuit protection device and method for secondary circuit of current transformer
  • Open-circuit protection device and method for secondary circuit of current transformer
  • Open-circuit protection device and method for secondary circuit of current transformer

Examples

Experimental program
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Effect test

Embodiment 1

[0047] Such as Figure 4 As shown, in this solution, a current transformer 11 secondary circuit open circuit protection device includes a casing 6, a monitoring module 14, a relay 10 and a voltage sensor 13, and the monitoring module 14, the relay 10 and the voltage sensor 13 are packaged in the casing 6 Among them, the contacts of the relay 10 and the voltage sensor 13 are all connected in parallel on the secondary circuit, the signal input end of the monitoring module 14 is connected to the signal line of the voltage sensor 13, and the high level output end of the monitoring module 14 is connected to the coil of the relay 10;

[0048] Two sets of wiring ports are arranged on the surface of the shell 6, wherein,

[0049] Such as figure 1 , figure 2 and image 3 As shown, port A1, port B1, port C1, port N1 and port D1 are arranged on the top of the housing 6, and fastening screws are provided on the front of the housing 6 corresponding to each port, and the port A1, port B...

Embodiment 2

[0065] Such as Figure 5 As shown, the current transformer secondary circuit open circuit protection device is installed on the second terminal block 9 of the site terminal box 7 through the card slot 5 on the back of the housing 6, and the secondary circuit of the current transformer 11 is connected through the first terminal block 8 The field terminal box 7 is connected to the shell 6 through the port A1, port B1, port C1 and port N1 on the top of the shell 6, and is led out to the load 12 terminal through the port A2, port B2, port C2 and port N2 on the bottom of the shell 6, The Hall current sensor 4 is arranged on the circuit main line channel on the shell 6, the monitoring module 14, the voltage sensor 13 and the relay 10 are packaged in the shell 6, the contacts of the relay 10 and the voltage sensor 13 are all connected in parallel on the secondary circuit, the monitoring module The signal input end of 14 connects the signal wire of voltage sensor 13, and Hall current ...

Embodiment 1 and Embodiment 2

[0068] Based on Embodiment 1 and Embodiment 2, this embodiment proposes a current transformer secondary circuit open circuit protection method, which is applied to the above current transformer secondary circuit open circuit protection device, including the following steps:

[0069] S1: The voltage sensor 13 monitors the voltage of the secondary circuit, and the Hall current sensor 4 monitors the current of the secondary circuit;

[0070] S2: The receiving unit of the monitoring module 14 receives the sampling data of the voltage sensor 13 and the Hall current sensor 4;

[0071] S3: The analysis unit of the monitoring module 14 performs threshold value judgment on the voltage sampled value input by the voltage sensor 13 and the current sampled value input by the Hall current sensor 4, and when any sampled value is greater than the threshold value, it is judged as abnormal data, and S3 is executed. Otherwise, continue to process the next set of data;

[0072] S4: The sending u...

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Abstract

The invention discloses an open circuit protection device and method for a secondary circuit of a current transformer, and the device comprises a housing, a monitoring module, a relay, and a voltage sensor, wherein the monitoring module, the relay and the voltage sensor are packaged in the housing, and a contact of the relay and the voltage sensor are in parallel connection with a secondary circuit; a signal input end of the monitoring module is connected with the signal line of the voltage sensor, and a high-level output end of the monitoring module is connected with the coil of the relay. The monitoring module, the relay and other elements are packaged in the shell, the voltage sensor, the relay and the like are connected to the secondary circuit in parallel inside the shell, and once the monitoring module finds that the secondary circuit is open, the contact of the relay is closed, so that a protection device similar to an air switch is obtained; the device is opposite to an air switch in principle, the air switch is disconnected when a loop is short-circuited, and the device is short-circuited when a secondary loop is disconnected.

Description

technical field [0001] The invention relates to the field of electrical equipment protection, in particular to a secondary circuit open circuit protection device and method for a current transformer. Background technique [0002] A current transformer is a device that transforms a large current in a power system into a small current, and its secondary side current is used for protection, measurement and metering. When the current transformer is in normal operation, its secondary side load impedance is small, similar to a short-circuit state, and the secondary voltage is low; when the secondary circuit is open, the current transformer easily enters an electromagnetic saturation state, and the secondary side will induce High voltage (up to 10,000 volts) can burn adjacent secondary equipment, and at the same time cause primary equipment to heat up and burn down or even explode. According to accident reports in the power industry, it is not uncommon for current transformers to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/00H02H7/04
CPCH02H7/00H02H7/042
Inventor 胡光伟杜继伟赵毅蒋有如陈鹏代博奥廖寅钦唐尧陈玉雪董洪松
Owner 国网四川省电力公司遂宁供电公司
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