CN207336683U - Transmission lines earth fault investigates warning device - Google Patents

Abstract

The utility model relates to a power transmission line grounding fault checking and alarm device, which belongs to the technical field of power transmission fault detection. The device includes a vacuum circuit breaker, a transformer, a grounding detection device, a shunt circuit breaker, a zero-sequence current transformer, and a leakage detection alarm; one end of the vacuum circuit breaker is connected to the three-phase busbars, and the other end is connected to A, B, and C of the transformer. The high-voltage windings are connected, the low-voltage windings A, B, and C of the transformer are connected to the grounding network of the substation through rheostats, and the neutral point of the high-voltage side of the transformer is connected to the grounding network of the substation; The output terminals of the current transformer and the zero-sequence current transformer are connected to the leakage detection alarm; the three-phase busbar is also connected to the grounding network of the substation through the grounding detection device, and the signal output terminal of the grounding detection device is connected to the vacuum circuit breaker. The utility model automatically judges the fault branch when a grounding fault occurs, has quick response and simple operation.

Description

Transmission line grounding fault troubleshooting and alarm device

technical field

The utility model relates to a power transmission line grounding fault checking and alarm device, which belongs to the technical field of power transmission fault detection.

Background technique

A substation is a power facility in the power system that transforms voltage, receives and distributes electric energy, controls the flow of power, and adjusts voltage. It connects the power grids of all levels of voltage through its transformers. The normal operation of substations is an important guarantee for industrial and agricultural production. However, in daily operation, faults, especially ground faults, inevitably occur in the transmission lines of substations. The current working procedure of the 10KV grounding alarm device in the substation is as follows: when a ground fault occurs in the 10KV line, it is necessary for the on-duty personnel or the dispatcher to try to pull each branch one by one to determine which line has the ground fault. The shortcoming of this system is: 1, speed is slow, operation is loaded down with trivial details. 2. For some important users (such as: large enterprises, large factories, etc.) that have high requirements for power quality, if the trial pull method is used, it will bring huge economic losses to these enterprises and lead to a high rate of user complaints.

Utility model content

The purpose of the utility model is to provide an investigation and alarm device which can detect and find out in time and accurately judge the grounding fault line.

In order to achieve the above object, the technical solution adopted by the utility model is:

A transmission line grounding fault troubleshooting alarm device, used in a three-phase four-wire transmission line, the alarm device includes a vacuum circuit breaker, a transformer, a grounding detection device, a shunt circuit breaker, a zero-sequence current transformer, and a leakage detection Alarm; one end of the vacuum circuit breaker is connected to the three-phase busbars A, B, and C respectively, and the other end is connected to the A, B, and C high-voltage windings of the transformer. The A, B, and C low-voltage windings of the transformer are connected to the substation grounding network through a rheostat. The neutral point on the high-voltage side of the transformer is connected to the grounding network of the substation; the branch circuit breakers and zero-sequence current transformers are arranged in turn on the branches of the A, B, and C three-phase buses, and the output terminals of the zero-sequence current transformers are connected to leakage detection and alarm The A, B, C three-phase busbars are also connected to the substation grounding grid through the grounding detection device, and the signal output terminal of the grounding detection device is connected to the vacuum circuit breaker.

Further, the vacuum circuit breaker is a permanent magnet vacuum circuit breaker.

Further, the rheostat is a sliding rheostat.

Further, the resistance range of the sliding rheostat is 0-100Ω, and the power of the sliding rheostat is 30kW.

Further, the electric leakage detection alarm includes an amplifying circuit, an indicator light and a horn connected to the output end of the amplifying circuit.

Further, the transformer is a 35KV30KW direct transformer.

Further, the checking and alarming device is used for a 10KV transmission line; the grounding detection device is a 10KV grounding detection device, and the branch circuit breaker is a 10KV branch circuit breaker.

Owing to adopting above-mentioned technical scheme, the beneficial technical effect that the utility model obtains has:

The utility model can quickly and accurately judge the shunt where the grounding fault occurs without breaking each shunt, and avoids the loss caused to the related enterprises due to the breaking of the normally working shunt.

The utility model can automatically judge the fault branch when a ground fault occurs, and has fast response speed and simple operation.

The utility model utilizes the zero-sequence current generated when a grounding fault occurs to be amplified and processed by an electric leakage detection alarm, and then drives an indicator light and a horn to generate an audible and visual alarm, without additional operations, and can effectively improve safety.

Description of drawings

Fig. 1 is a schematic diagram of the utility model;

Among them, 1. Three-phase bus, 2. No. 1 shunt, 3. No. 2 shunt, 4. Vacuum circuit breaker, 5. Grounding detection device, 6. Transformer, 7. Shunt circuit breaker, 8. Zero sequence current Transformer, 9. Leakage detection alarm, 10. Rheostat, 11. Substation grounding grid.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail:

The utility model discloses a ground fault checking and alarming device for a transmission line, which is used in a three-phase four-wire transmission line. The utility model is mainly used in the transmission line of the 10KV substation, but not limited to the transmission line of the 10KV substation.

The alarm device includes a vacuum circuit breaker, a transformer, a grounding detection device, a shunt circuit breaker, a zero-sequence current transformer, and an electric leakage detection alarm. One end of the vacuum circuit breaker is connected to the three-phase lines A, B, and C respectively, and the other end is connected to the A, B, and C high-voltage windings of the transformer. The A, B, and C low-voltage windings of the transformer are connected to the grounding grid of the substation through resistors. The neutral point is connected to the grounding grid of the substation; a shunt circuit breaker and a zero-sequence current transformer are arranged in sequence on the branches of the three-phase lines A, B, and C, and the output end of the zero-sequence current transformer is connected to a leakage detection alarm; A , B, and C three-phase lines are also connected to the substation grounding network through the grounding detection device, and the signal output end of the grounding detection device is connected to the vacuum circuit breaker. The ground detection device and the substation ground grid are existing equipment in the substation.

The leakage detection alarm in the utility model includes an amplifying circuit and an indicator light and a horn connected to the output end of the amplifying circuit, wherein the amplifying circuit is used to amplify the induced current generated by the zero-sequence current transformer so as to drive the indicator light and the horn to operate , reminding the staff of the specific branch where the ground fault occurs.

The vacuum circuit breaker in the utility model is a permanent magnet vacuum circuit breaker. The permanent magnet vacuum circuit breaker has good reliability, long service life and rapid response, and can ensure the long-term stable operation of the entire alarm device.

The three rheostats in the utility model are preferably sliding rheostats. Using the sliding rheostats can adjust the reactance value of the high-voltage side of the direct transformer, thereby adjusting the 10KV grounding current value, so that the device can operate reliably without causing the grounding current to be too large. When it is too large, it may cause the overcurrent protection device of the 10KV device to trip. This setting ensures the reliability of the alarm device. The resistance range of the sliding rheostat in the utility model is preferably set to 0-100Ω, and the power of the sliding rheostat is preferably set to 30kW.

The investigation and alarm device in the utility model is mainly used for 10KV transmission lines; the grounding detection device is a 10KV grounding detection device, and the branch circuit breaker is a 10KV branch circuit breaker. Transformer in the utility model is generally 35KV30KW direct change.

In the schematic diagram of the alarm device in Fig. 1, it only shows that there are two branches, that is, No. 1 branch 2 and No. 2 branch 3. There may be several branches in the actual transmission line, and the arrows in Fig. 1 Indicates the direction of the leakage current.

Taking the No. 1 shunt as an example, the working principle of the present invention is explained: Assuming that the C phase of No. 1 shunt 2 of 10KV is grounded due to a fault, the 10KV grounding detection device first detects the grounding signal and then sends a signal to the permanent magnet vacuum circuit breaker. Output a control signal to make it close for 2 seconds (automatically disconnect after 2 seconds). During its closing period, the phase-to-earth leakage current _IL of No. 1 shunt flows into the ground from phase C, and then flows from the ground into the substation grounding grid 11 and then from the substation The grounding grid 11 flows into the neutral point of the 35KV30KW direct transformer high-voltage side, and then returns to the A and B phases through the A and B high-voltage windings respectively. It can be seen from the figure that the current flowing out of the C-phase of the No. 1 branch does not pass through the No. 1 branch. The C-phase of the circuit flows back, thus generating residual current, that is, zero-sequence current, which will generate an induced voltage in the secondary winding of the zero-sequence current transformer, which is sent to the leakage detection alarm for amplification and After processing, the indicator light and the horn are driven to generate an audible and visual alarm.

The utility model detects the leakage current returning to the three-phase bus through the transformer by setting a zero-sequence current transformer on the basis of the existing substation grounding grid and the grounding detection device. The utility model has a simple structure and is convenient to use.

In the utility model, when the power transmission line leaks, the grounding detection device first detects the grounding signal and then outputs a control signal to the permanent magnet vacuum circuit breaker to make it close for 2 seconds (it will automatically break after 2 seconds). During the closing period, it can quickly A branch of a faulty transmission line is detected. At the same time, it can also prevent the leakage current from continuously flowing back to the three-phase busbar and possibly adversely affecting other normal shunts.

The utility model can quickly and accurately judge the shunt where the ground fault occurs without breaking each shunt, avoiding the loss caused to the relevant enterprises due to the breaking of the normally working shunt, and ensuring the normal production of the enterprise , while reducing the complaint rate of power supply companies. The utility model not only has the function of alarm, but also has the function of troubleshooting and judging the fault branch, which reduces the time from the occurrence of the fault to its elimination, and reduces the loss of related enterprises as much as possible.

The utility model can automatically judge the faulty shunt when a grounding fault occurs, and has fast response speed and simple operation.

The utility model utilizes the zero-sequence current generated when a grounding fault occurs to be amplified and processed by an electric leakage detection alarm, and then drives an indicator light and a horn to generate an audible and visual alarm, without additional operations, and can effectively improve safety.

Claims (7)

1. a kind of transmission lines earth fault investigates warning device, it is characterised in that：For in the transmission line of electricity of three-phase four-wire system, The warning device includes vacuum circuit breaker（4）, transformer（6）, ground detection device（5）, shunt circuitbreaker（7）, zero sequence electricity Current transformer（8）, detection of electrical leakage alarm（9）；Vacuum circuit breaker（4）One end and A, B, C three-phase bus respectively（1）Connection, separately One end and transformer（6）A, B, C high-voltage winding connection, transformer（6）A, B, C low pressure winding pass through rheostat（10）With change Power station grounded screen（11）Connection, transformer（6）High-pressure side neutral point and grounding net of transformer substation（11）Connection；A, B, C three-phase bus （1）Shunt circuitbreaker is set gradually in the branch separated（7）And zero sequence current mutual inductor（8）, zero sequence current mutual inductor（8）It is defeated Outlet connects detection of electrical leakage alarm（9）；A, B, C three-phase bus（1）Line also passes through ground detection device（5）With substation grounding Net（11）Connection, ground detection device（5）Signal output part and vacuum circuit breaker（4）Connection.

2. transmission lines earth fault according to claim 1 investigates warning device, it is characterised in that：Vacuum circuit breaker （4）For permanent magnet type vacuum circuit-breaker.

3. transmission lines earth fault according to claim 1 investigates warning device, it is characterised in that：The rheostat （10）For slide rheostat.

4. transmission lines earth fault according to claim 3 investigates warning device, it is characterised in that：Slide rheostat Standard resistance range is 0~100 Ω, and the power of slide rheostat is 30kW.

5. transmission lines earth fault according to claim 1 investigates warning device, it is characterised in that：Detection of electrical leakage is alarmed Device（9）The indicator light and loudspeaker being connected including amplifying circuit and with amplification circuit output end.

6. transmission lines earth fault according to claim 1 investigates warning device, it is characterised in that：The transformer is 35KV30KW directly becomes.

7. warning device is investigated according to claim 1~6 any one of them transmission lines earth fault, it is characterised in that：Institute State investigation warning device and be used for 10KV transmission lines of electricity；Ground detection device（5）For 10KV ground detection devices, shunt circuitbreaker （7）For 10KV shunt circuitbreakers.