CN217469442U

CN217469442U - Leakage protection device for obtaining zero sequence current to perform leakage protection

Info

Publication number: CN217469442U
Application number: CN202221542381.2U
Authority: CN
Inventors: 曹超君; 杜冲; 张宏亮; 陈明安
Original assignee: Lankao Zhongchuang Power Technology Service Co ltd
Current assignee: Lankao Zhongchuang Power Technology Service Co ltd
Priority date: 2022-06-20
Filing date: 2022-06-20
Publication date: 2022-09-20
Anticipated expiration: 2032-06-20

Abstract

The utility model discloses an acquire zero sequence current and carry out earth leakage protection's earth leakage protection device, including open type mutual-inductor, protection unit, first switch, power, test coil and test switch, open type mutual-inductor's iron core cover is located near metering control case's high tension cable of registering one's residence outside, open type mutual-inductor's induction coil winding is in on the iron core and with protection unit's incoming wire terminal passes through the wire and connects, protection unit's leading-out terminal with the tripping coil binding post of first switch passes through the wire and connects, induction coil, the power with test coil passes through test line and connects, test coil twine in on the iron core, test switch concatenates in on the test line. By adopting the open type mutual inductor, the high-voltage cable entering the household can enter the mutual inductor from the opening, and the installation is very convenient; the leakage protection device is additionally provided with a test coil, and has the function of periodically and randomly detecting the leakage protection system.

Description

Leakage protection device for obtaining zero sequence current to perform leakage protection

Technical Field

The utility model relates to an electric power transmission technical field, concretely relates to acquire zero sequence current and carry out earth leakage protection's earth leakage protection device.

Background

The 10KV power supply line of the power supply company supplies power to the users with 10KV voltage class, the damage of the surface (insulating layer) of the branch line (buried line, etc.) of the house or the electric leakage after the high-voltage equipment on the house line is damaged can cause the trip of the main line at this time, which affects the power supply of the whole line, which is not preferable. Generally, a circuit breaker and a metering device (generally called a head switch) are installed at the upper end of an electric pole to perform overcurrent quick-break protection. One of the existing first switches is to obtain zero sequence current through a zero sequence transformer, and the zero sequence transformer with a rectangular iron core is added on a wire outlet terminal of the switch by a switch manufacturer, and the installation mode has complex process and high cost and cannot be replaced and maintained; the rectangular iron core has long magnetic circuit and low measurement accuracy, and the iron core is sleeved on the outgoing line terminal, so that the short circuit risk is still caused although strict insulation treatment is carried out; the other type is that current protection and leakage protection are mixed together, the secondary current circuit is long, and when the whole current loop breaks down, the current loop is as follows: open circuit, short circuit, electric leakage all can appear the malfunction or lose the earth leakage protection function.

SUMMERY OF THE UTILITY MODEL

Therefore, the embodiment of the utility model provides an acquire zero sequence current and carry out earth leakage protection's earth leakage protection device to solve among the prior art because the installation that the zero sequence transformer that adopts rectangular core leads to is complicated, with high costs, can not change and overhaul and current protection and earth leakage protection mix together and the malfunction that leads to, lose the technical problem of earth leakage protection function.

In order to achieve the above object, the present invention provides the following technical solutions:

the utility model provides an acquire zero sequence current and carry out earth leakage protection's earth leakage protection device, includes open type mutual-inductor, protection unit and first switch (fix on the pole at entrance branch line place), open type mutual-inductor's induction coil with protection unit's incoming line terminal passes through the wire and connects, protection unit's leading-out terminal with trip coil binding post of first switch passes through the wire and connects.

Furthermore, an iron core of the open-type mutual inductor is sleeved outside a household high-voltage cable near a metering control box (fixed on an electric pole where a household branch is located and lower than a first switch), and the induction coil is wound on the iron core.

Furthermore, the leakage protection device further comprises a power supply and a test coil, wherein the power supply is connected with the test coil through a test circuit, and the test coil is wound on the iron core.

Further, the earth leakage protection device further comprises a test switch, and the test switch is connected in series on the test circuit.

Optionally, the protection unit is a 6000 microcomputer comprehensive protection device.

The embodiment of the utility model provides a have following advantage:

the leakage protection device provided by the utility model has low cost, adopts the open-type mutual inductor, the high-voltage cable of the house can enter the mutual inductor from the opening, and the laid high-voltage cable of the house can be easily installed, thus having simple process and convenient installation, and being convenient for replacement and maintenance; and the open type mutual inductor has short magnetic circuit, high measurement precision, strong anti-interference capability, simple wiring and complete separation from other circuits, thereby having high reliability. The current protection unit (also called as a protection module) is used for judging the magnitude of the zero sequence current, when the magnitude exceeds a certain value, the zero sequence current is fed back to the first switch, and the first switch trips based on a feedback electric signal, so that the household branch circuit is disconnected from the main circuit, and the leakage protection is implemented. The leakage protection device is additionally provided with a test coil, and has the function of detecting the leakage protection system at any time at regular intervals. The leakage protection function is added to the switch which has not been operated with leakage protection, and the installation and maintenance are convenient. Has the characteristics of higher safety, reliability and low cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structure, ratio, size and the like shown in the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by people familiar with the technology, and are not used for limiting the limit conditions which can be implemented by the present invention, so that the present invention has no technical essential significance, and any structure modification, ratio relationship change or size adjustment should still fall within the scope which can be covered by the technical content disclosed by the present invention without affecting the efficacy and the achievable purpose of the present invention.

Fig. 1 is a schematic view of a structure and an installation position of an electric leakage protection device for obtaining zero sequence current to perform electric leakage protection according to an embodiment of the present invention;

fig. 2 is a schematic view of connection and installation positions of an open-type transformer and a protection unit of the earth leakage protection device according to the embodiment of the present invention and a house-entering high-voltage cable;

fig. 3 is a schematic diagram of a connection relationship between the open-type transformer, the protection unit, the power supply and the test switch of the earth leakage protection device provided by the embodiment of the present invention.

In the figure: 1-open type mutual inductor, 2-protection unit, 3-metering control box, 4-household high-voltage cable, 5-power supply, 6-test switch and 7-first switch.

Detailed Description

The present invention is described in terms of specific embodiments, and other advantages and benefits of the present invention will become apparent to those skilled in the art from the following disclosure. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

As shown in fig. 1 to 3, the present embodiment provides an earth leakage protection device for obtaining zero sequence current to perform earth leakage protection, which includes an open-type transformer 1, a protection unit 2, a first switch 7, a power supply 5, a test coil, and a test switch 6.

The open-type transformer 1 can also be replaced by a core-through transformer (at this time, the operated power supply line is inconvenient to be transformed), and the open-type transformer 1 is used for introduction in the embodiment. An iron core of the open type mutual inductor 1 is sleeved outside a household high-voltage cable 4 near a metering control box 3, an induction coil of the open type mutual inductor is wound on the iron core, and the induction coil is connected with an incoming terminal of a protection unit 2 through a wire; generally, both ends of the induction coil are fixed to terminals of the open-type transformer 1. The protection unit 2 is also called a protection module, which is a judgment module for judging the magnitude of the zero sequence current, and a 6000 microcomputer integrated protection device or other similar devices can be adopted as the protection unit 2. The outlet terminal of the protection unit 2 is connected with the trip coil connecting terminal of the first switch 7 through a lead. The primary switch 7 is based on the judgment of the protection unit 2, if the zero sequence current is judged to reach the preset value by the protection unit 2, the protection unit 2 sends an electric signal or conducts current to the trip coil, the current flows through the trip coil, and the primary switch 7 executes a trip action; on the contrary, the first switch 7 does not act, i.e. does not trip.

In this embodiment, the iron core of the open-type transformer 1 is not only wound with the induction coil, but also wound with the test coil, when the test coil is powered on, the induction coil generates a test current, the test current is transmitted to the protection unit 2 as the zero sequence current, and after the protection unit 2 determines the size, the primary switch 7 performs a trip or no-trip action based on the determination structure of the protection unit 2. The power supply 5 is connected with the test coil through a test circuit, and the test switch 6 is connected to the test circuit in series.

As shown in fig. 1, it is a display protection unit 2 so that the protection unit 2 is disposed outside a metering control box 3; in practice, the protection unit 2 is often provided inside the metering control box 3. The electrical connection of the metering control box 3 to the first switch 7 is not subject to the protection of the present application and is therefore not described here.

The earth leakage protection device that this embodiment provided is with low costs, simple to operate, and it is reliable to use. By adopting the open type mutual inductor 1, the high-voltage cable 4 entering the household can enter the mutual inductor from the opening, and the laid high-voltage cable 4 entering the household can be easily installed, so that the installation is very convenient; and the magnetic circuit is short, the measurement accuracy is high, the anti-interference ability is strong, the wiring is simple, and the circuit is completely separated from other circuits, so the reliability is high. The existing protection unit 2 (also called as a protection module) is used for judging the magnitude of the zero sequence current, when the magnitude exceeds a certain value, the zero sequence current is fed back to the head switch 7, and the head switch 7 trips based on a feedback electric signal, so that the household branch circuit is disconnected from the main circuit, and the leakage protection is implemented. The leakage protection device is additionally provided with a test coil, and has the function of detecting the leakage protection system at any time at regular intervals. The leakage protection function is added to the switch which has not been operated with leakage protection, and the installation and maintenance are convenient.

Although the invention has been described in detail with respect to the general description and the specific embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made based on the invention. Therefore, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. The utility model provides an acquire zero sequence current and carry out earth leakage protection's earth leakage protection device which characterized in that, includes open type mutual-inductor, protection unit and first switch, open type mutual-inductor's induction coil with the incoming line terminal of protection unit passes through the wire and connects, the outlet terminal of protection unit with trip coil binding post of first switch passes through the wire and connects.

2. An earth leakage protection device according to claim 1, characterized in that the iron core of the open-type mutual inductor is sleeved outside a high-voltage cable for household near the metering control box, and the induction coil is wound on the iron core.

3. A residual current device according to claim 2, characterized in that said residual current device further comprises a power supply and a test coil, said power supply and said test coil are connected by a test line, said test coil is wound on said iron core.

4. A residual current device as claimed in claim 3, characterized in that said residual current device further comprises a test switch, said test switch being connected in series to said test line.

5. An earth leakage protection device according to claim 1, characterized in that the protection unit is a 6000 microcomputer integrated protection device.