CN212137262U

CN212137262U - Neutral point management device

Info

Publication number: CN212137262U
Application number: CN202020459927.2U
Authority: CN
Inventors: 姜涛
Original assignee: HEFEI KAIGAO ELECTRICAL EQUIPMENT CO Ltd
Current assignee: HEFEI KAIGAO ELECTRICAL EQUIPMENT CO Ltd
Priority date: 2020-04-01
Filing date: 2020-04-01
Publication date: 2020-12-11
Anticipated expiration: 2030-04-01

Abstract

The utility model relates to an electric power system technical field just discloses a neutral point management device, including grounding transformer ZB, single-phase high voltage isolator QS, single-phase eddy current drive quick breaker ARS, zinc oxide arrester MOV, microcomputer controller ZK, resistance element BLR, zero sequence current transformer TA, grounding transformer ZB's high-pressure side A is connected with the three-phase high-voltage electricity's generating line electricity, grounding transformer ZB's big N-terminal is connected with single-phase high voltage isolator QS's upper end electricity, single-phase high voltage isolator QS's lower extreme is connected with single-phase eddy current drive quick breaker ARS's upper end electricity, single-phase high voltage isolator QS's lower extreme is connected with zinc oxide arrester MOV's upper end electricity. This neutral point management device drives quick circuit breaker ARS through single-phase vortex and comes the input and the withdraw from of control resistance component BLR, can effectively eliminate arc light ground connection overvoltage, avoids the electrical equipment damage accident that arc light ground connection arouses, improves the power supply reliability.

Description

Neutral point management device

Technical Field

The utility model relates to an electric power system technical field specifically is a neutral point management device.

Background

The neutral point grounding mode of the power distribution network is a very strong technical problem, and relates to a plurality of aspects such as technology, economy, safety and the like, the neutral point of the 7.2-35kV power distribution network in China adopts a non-effective grounding system, and the grounding modes mainly comprise three modes, namely a neutral point ungrounded system (mainly suitable for a smaller power system, and the capacitance current is less than 10A), and a resonance grounding system adopting an arc suppression coil grounding mode; and thirdly, a large-current grounding system adopting a small-resistance grounding mode. The main function of the arc suppression coil is to compensate the single-phase grounding capacitance current of the system, and the arc is automatically extinguished after compensation, but still has many problems from the past: 1. when a single-phase ground fault occurs, the non-fault voltage to earth rises above the phase voltage of √ 3, the duration is long, the whole system equipment is affected, and the second point insulation breakdown is possibly caused, so that the accident expansion accident is caused, 2, the arc suppression coil only compensates the power frequency capacitance current, the current actually passing through the grounding point not only has the capacitance current but also contains a large amount of high frequency current and resistance current, and the continuous burning of the electric arc can be maintained only by the high frequency current and the resistance current in serious conditions, which cannot be solved by the arc suppression coil, 3, the single-phase ground fault circuit is difficult to find, the fault point current after compensation is reduced, the line selection success rate of a plurality of small-current ground line selection methods is not ideal, a trial pulling method is often adopted, the non-fault line is powered off in short time, the operation overvoltage is caused, and the overvoltage level is higher 4, the arc suppression coil has large volume, more components, high cost, complex measurement and calculation of capacitance current change, insufficient accuracy, complex operation and maintenance, and the small-resistance grounding system has the main advantages of low overvoltage level of the system, capability of rapidly finding out a grounding fault circuit and disconnecting the fault circuit, but the following defects exist: 1. the power supply reliability is low, when the system is grounded by single-phase intermittent arc light or instantaneous grounding caused by other factors, 2, the system has poor safety, when single-phase grounding occurs, the grounding current is large for a long time, great threat to the people near the grounding point, the large current can burn out other equipment, 3, when the fault line can not be cut off rapidly, the large current is always continuous, the resistor can be burned out (the general current flowing time of the resistor is 10S), the large current continuously burns out the cable or other equipment to cause short-circuit accidents, 4, the interference to the communication is serious, when the system generates single-phase grounding, the larger grounding current thereof generates great interference to communication equipment, communication lines, secondary lines and equipment, therefore, we have designed a neutral point management apparatus to be applied to a system in which a neutral point is not grounded and a system in which a neutral point is grounded via a small resistance.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

The utility model provides a to prior art not enough, the utility model provides a neutral point management device possesses the advantage that prevents the electrical equipment damage, has solved the problem that there is the defect in current distribution network neutral point contact local form.

(II) technical scheme

In order to achieve the above object, the utility model provides a following technical scheme: a neutral point management device comprises a grounding transformer ZB, a single-phase high-voltage isolating switch QS, a single-phase eddy current driving quick breaker ARS, a zinc oxide arrester MOV, a microcomputer controller ZK, a resistance element BLR and a zero sequence current transformer TA, wherein the high-voltage end A of the grounding transformer ZB is electrically connected with a bus of three-phase high-voltage electricity, the large N end of the grounding transformer ZB is electrically connected with the upper end of the single-phase high-voltage isolating switch QS, the lower end of the single-phase high-voltage isolating switch QS is electrically connected with the upper end of the single-phase eddy current driving quick breaker ARS, the lower end of the single-phase high-voltage isolating switch QS is electrically connected with the upper end of the zinc oxide arrester MOV, the lower end of the zinc oxide arrester MOV is grounded, the lower end of the single-phase eddy current driving quick breaker ARS is electrically connected with the input end of the microcomputer controller ZK, the lower end of the BLR is electrically connected with the upper end of the zero sequence current transformer TA, and the lower end of the BLR is grounded.

Preferably, the single-phase eddy current driving fast circuit breaker ARS is an electrical component having the same function as a vacuum contactor or a switch.

Preferably, the single-phase eddy current driving fast breaker ARS and the resistance element BLR are grounded in series, the switching-off time of the single-phase eddy current driving fast breaker ARS is less than or equal to 5ms, and the switching-on time of the single-phase eddy current driving fast breaker ARS is less than or equal to 20 ms.

(III) advantageous effects

Compared with the prior art, the utility model provides a neutral point management device possesses following beneficial effect:

1. this neutral point management device, come the input and withdraw from of control resistance component BLR through single-phase vortex drive quick circuit breaker ARS, can effectively eliminate arc light ground connection overvoltage, avoid the electrical equipment damage accident that arc light ground connection arouses, improve the power supply reliability, this single-phase vortex drive quick circuit breaker ARS's separating brake time is less than or equal to 5ms, closing brake time is less than or equal to 20ms, and establish ties ground connection with resistance component BLR, utilize the quick characteristics of this circuit breaker, quick accurate input withdraws from the resistance, through the accurate trip fault line of instantaneous increase fault point electric current, the difficult problem that can not select the fault line has been solved.

2. This neutral point management device adopts single-phase eddy current drive quick circuit breaker ARS and resistance element BLR series connection ground connection, switches the neutral point ground connection mode between ungrounded mode and through the small resistance ground connection mode, does not throw resistance to transient ground connection, puts into resistance 200ms to permanent single-phase ground connection, and the excision that the fault line can be accurate has avoided long-term heavy current to cause the threat to circuit and equipment, has solved the poor problem of burning resistance and small resistance system power supply reliability.

3. The neutral point management device adopts the resistance element BLR, has the advantages of small volume, convenient installation, large absorbed energy and the like, is matched with the single-phase eddy current driving rapid circuit breaker ARS to limit single-phase grounding current, and ensures that the grounding current is in a safety range and meets the requirement of a single-phase grounding trip fault line.

4. The neutral point management device adopts a microcomputer controller, a power supply module, a signal acquisition module, a switching value acquisition module and a display module are arranged on the controller, the microcomputer controller acquires the secondary voltage measured by a voltage transformer in a system, can accurately judge a single-phase earth fault through the change of the voltage, and controls the input and the exit of a resistance element BLR through controlling the switching of a single-phase eddy current driving rapid circuit breaker ARS, so as to accurately cut off a fault line.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

Referring to fig. 1, a neutral point management apparatus includes a grounding transformer ZB, a single-phase high-voltage isolating switch QS, a single-phase eddy current driving fast breaker ARS, a zinc oxide arrester MOV, a microcomputer controller ZK, a resistor element BLR, and a zero sequence current transformer TA, wherein a high voltage terminal a of the grounding transformer ZB is electrically connected to a three-phase high voltage bus, a high voltage terminal A, B, C of the grounding transformer ZB is connected to a three-phase high voltage bus A, B, C, a large N terminal of the grounding transformer ZB is electrically connected to an upper terminal of the single-phase high-voltage isolating switch QS, a lower terminal of the single-phase high-voltage isolating switch QS is electrically connected to an upper terminal of the single-phase eddy current driving fast breaker ARS, the single-phase eddy current driving fast breaker ARS is an electrical component having the same function as a vacuum contactor and a switch, and the input and exit of a neutral point ground resistance is controlled by, the single-phase eddy current driving fast breaker ARS is grounded in series with a resistance element BLR, the switching-off time of the single-phase eddy current driving fast breaker ARS is less than or equal to 5ms, the switching-on time of the single-phase eddy current driving fast breaker ARS is less than or equal to 20ms, the fast characteristic of the single-phase eddy current driving fast breaker ARS is utilized, the resistance is quickly and accurately input and quit, the problem that a fault line can not be selected is solved by instantly and accurately jumping off the fault line by instantly increasing the current of a fault point, the lower end of a single-phase high-voltage isolating switch QS is electrically connected with the upper end of a zinc oxide arrester MOV, the lower end of the zinc oxide arrester MOV is grounded, the lower end of the single-phase eddy current driving fast breaker ARS is electrically connected with the input end of a microcomputer controller ZK, the microcomputer controller ZK can accurately judge a single-phase ground fault by monitoring the change of, the single-phase eddy current driving quick circuit breaker ARS is accurately matched with relay protection to cut off a fault line, the lower end of the single-phase eddy current driving quick circuit breaker ARS is electrically connected with the upper end of a resistance element BLR, the lower end of the BLR is electrically connected with the upper end of a zero sequence current transformer TA, the lower end of the BLR is grounded, the resistance element BLR is an electrical appliance element with the same effect as a capacitance element and an inductance element, and the resistance element BLR is adopted and has the advantages of small size, convenience in installation, large absorbed energy and.

The electrical components presented in the document are all electrically connected with an external master controller and 220V mains, and the master controller can be a conventional known device controlled by a computer or the like.

When the system is in use and normally put into operation, the single-phase eddy current drives the rapid breaker ARS to be in a brake-off state, a neutral point of the system operates in a non-grounding mode, the microcomputer controller ZK acquires signals of three-phase voltages Ua, Ub, Uc, open triangular voltage UO and the like of a voltage transformer cabinet of the system in real time, when the system has overvoltage, the MOV of the zinc oxide arrester is firstly put into operation to limit the system overvoltage in a safety range allowed by the insulation of electrical equipment, when the system generates single-phase grounding, the microcomputer controller acquires signals of three-phase voltages Ua, open triangular voltage UO and the like provided by a voltage transformer PT and carries out calculation processing through the microcomputer processor to judge grounding properties and grounding phases and process the signals, if the generated fault is instantaneous arc grounding, the microcomputer controller detects, analyzes and judges the fault in real time and does not send a closing signal to the single-phase eddy current driving the rapid breaker ARS, the resistance is not put into, the system resumes normal operation after the instantaneous arc light is over, if the fault is sustained arc light grounding or permanent metal grounding, the microcomputer controller detects, analyzes and judges the fault in real time, a closing signal is sent to the single-phase eddy current driving fast circuit breaker ARS, the resistance is put into, the putting time is 200ms, the neutral point grounding mode is changed into a small resistance grounding system instantly when the resistance is put into, the neutral point forms a loop with the single-phase grounding point through resistance grounding when the single-phase is grounded, the large current flows through the fault point, the grounding circuit is cut off by microcomputer protection action, the microcomputer protection is refused after the resistance is put into when the single-phase is grounded, the microcomputer controller sends a brake opening signal to the single-phase eddy current driving; the microcomputer controller sends out sound and light alarm signals and displays the fault type and the fault phase, and waits for the processing of the operator on duty.

In conclusion, the neutral point management device controls the switching-in and the switching-out of the resistance element BLR through the single-phase eddy current driving quick circuit breaker ARS, can effectively eliminate arc grounding overvoltage, avoids electrical equipment damage accidents caused by arc grounding, and improves power supply reliability, the switching-off time of the single-phase eddy current driving quick circuit breaker ARS is less than or equal to 5ms, the switching-on time is less than or equal to 20ms, and the single-phase eddy current driving quick circuit breaker ARS is connected with the resistance element BLR in series for grounding.

This neutral point management device adopts single-phase eddy current drive quick circuit breaker ARS and resistance element BLR series connection ground connection, switches the neutral point ground connection mode between ungrounded mode and through the small resistance ground connection mode, does not throw resistance to transient ground connection, puts into resistance 200ms to permanent single-phase ground connection, and the excision that the fault line can be accurate has avoided long-term heavy current to cause the threat to circuit and equipment, has solved the poor problem of burning resistance and small resistance system power supply reliability.

The neutral point management device adopts the resistance element BLR, has the advantages of small volume, convenient installation, large absorbed energy and the like, is matched with the single-phase eddy current driving rapid circuit breaker ARS to limit single-phase grounding current, and ensures that the grounding current is in a safety range and meets the requirement of a single-phase grounding trip fault line.

The neutral point management device adopts a microcomputer controller, a power supply module, a signal acquisition module, a switching value acquisition module and a display module are arranged on the controller, the microcomputer controller acquires the secondary voltage measured by a voltage transformer in a system, can accurately judge a single-phase earth fault through the change of the voltage, and controls the input and the exit of a resistance element BLR through controlling the switching of a single-phase eddy current driving rapid circuit breaker ARS, so as to accurately cut off a fault line.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a neutral point management device, includes earthing transformer ZB, single-phase high voltage isolator QS, single-phase eddy current drive quick circuit breaker ARS, zinc oxide arrester MOV, microcomputer control ware ZK, resistance element BLR, zero sequence current transformer TA, its characterized in that: the high-voltage end A of the grounding transformer ZB is electrically connected with a three-phase high-voltage electric bus, the large N end of the grounding transformer ZB is electrically connected with the upper end of a single-phase high-voltage isolating switch QS, the lower end of the single-phase high-voltage isolating switch QS is electrically connected with the upper end of a single-phase eddy current driving quick breaker ARS, the lower end of the single-phase high-voltage isolating switch QS is electrically connected with the upper end of a zinc oxide arrester MOV, the lower end of the zinc oxide arrester MOV is grounded, the lower end of the single-phase eddy current driving quick breaker ARS is electrically connected with the input end of a microcomputer controller ZK, the lower end of the single-phase eddy current driving quick breaker ARS is electrically connected with the upper end of a resistor element BLR, the lower end of the resistor element BLR.

2. A neutral point management apparatus according to claim 1, wherein: the single-phase eddy current driving quick breaker ARS is an electrical appliance element with the same effect as a vacuum contactor and a switch.

3. A neutral point management apparatus according to claim 1, wherein: the single-phase eddy current driving rapid breaker ARS is connected with the resistance element BLR in series and grounded, the switching-off time of the single-phase eddy current driving rapid breaker ARS is less than or equal to 5ms, and the switching-on time of the single-phase eddy current driving rapid breaker ARS is less than or equal to 20 ms.