CN214337565U

CN214337565U - Transfer resistance adjustable active intervention arc extinguishing device

Info

Publication number: CN214337565U
Application number: CN202120638089.XU
Authority: CN
Inventors: 高志辉; 张振江
Original assignee: HEBEI XUHUI ELECTRIC CO Ltd
Current assignee: HEBEI XUHUI ELECTRIC CO Ltd
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2021-10-01
Anticipated expiration: 2031-03-30

Abstract

The utility model discloses a transfer resistance adjustable initiative intervention arc extinguishing device, including controller, setting arc extinction branch road between generating line and ground and can judge the trouble that looks mutual transfer ground current according to system's ground state automatic start and cut the branch road mutually, the trouble is thrown mutually and is cut the branch road and including connecting the looks shunt switch on generating line three-phase line respectively, and three looks shunt switch's the other end connects in resistance transfer circuit's one end altogether, resistance transfer circuit's other end ground connection, arc extinction branch road, three looks shunt switch and resistance transfer circuit's controlled end difference connection director's output. The utility model discloses a mode of adjusting transfer resistance size can realize judging looks, restriction short-circuit current when judging the phase error, the selection of ground connection circuit and the discernment that ground fault withdrawed from etc. has improved the route selection accuracy to the impact that produces the system when having reduced resistance transfer circuit tentative and withdrawing from has effectively improved the safe operation level of system.

Description

Transfer resistance adjustable active intervention arc extinguishing device

Technical Field

The utility model relates to a distribution equipment technical field, especially an arc extinguishing device.

Background

The single-phase earth fault is one of the most common faults of the power distribution network, the active intervention arc extinction technology is applied to the medium-voltage power distribution network, three single phase-to-earth switches are provided, when the single-phase earth fault occurs in the system, the fault phase shunt switch is closed, the earth phase is grounded in time, the current of a fault point is quickly reduced to zero, a mechanism for generating electric arcs is destroyed by utilizing a voltage arc extinction principle, the arc extinction effect which is not influenced by the size of the electric arc current is realized, and the probability of personal injury and death of the fault point is further reduced. However, the active intervention arc extinction technology still has the following problems: 1) in general, after grounding occurs, a fault line is selected by a line selection device before and after grounding current transfer, and if line selection is wrong, secondary line selection cannot be performed because all grounding currents are transferred; 2) when the system is tentatively withdrawn by judging whether the grounding is lost, the system is impacted more or less, ferromagnetic resonance is easily excited to cause PT fuse blowing, and even burning accidents.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that needs to solve provides a transfer resistance adjustable initiative intervention arc extinguishing device, can carry out the secondary route selection, also can be used to carry out the judgement that ground connection disappears to improve the route selection rate of accuracy, to the impact of system, effectively improve the safe operation level of system when reducing the heuristic and withdraw from.

In order to solve the technical problem, the utility model adopts the following technical proposal.

The transfer resistance-adjustable active intervention arc extinction device comprises a controller and an arc extinction branch which is arranged between a bus and the ground and can adjust an inductive reactance value according to a system running state under the instruction of the controller so as to realize an arc extinction function, a fault phase switching branch which can automatically start judging and transfer grounding current according to a system grounding state is also arranged between the bus and the ground, and controlled ends of the arc extinction branch and the fault phase switching branch are respectively connected with an output end of the controller; the fault phase switching branch circuit comprises phase shunt switches respectively connected to three phase lines of a bus, the other ends of the three phase shunt switches are connected to one end of a resistance transfer circuit in common, the other end of the resistance transfer circuit is grounded, and the controlled ends of the three phase shunt switches and the resistance transfer circuit are respectively connected with the output end of a controller.

The resistance transfer circuit comprises a transfer grounding switch, a first transfer resistor and a series branch circuit formed by a second transfer resistor and a transfer resistor switch which are connected in parallel, and the three phase shunt switches comprise an A phase shunt switch, a B phase shunt switch and a C phase shunt switch; the controlled ends of the transfer grounding switch and the transfer resistance switch are respectively connected with the output end of the controller.

According to the active interference arc extinction device with the adjustable transfer resistors, the resistance values of the first transfer resistor and the second transfer resistor can be equal and are both 50 omega.

According to the active intervention arc extinction device with the adjustable transfer resistance, a current transformer is connected in series on a circuit between the resistance transfer circuit and the ground, the output end of the current transformer is connected with two-phase overcurrent protection devices, the output ends of the two-phase overcurrent protection devices are respectively connected with the controlled ends of the three phase shunt switches, and the two-phase overcurrent protection devices are connected with the controller.

The transfer resistance adjustable active intervention arc suppression device is characterized in that the arc suppression branch comprises a grounding transformer, a vacuum high-voltage contactor, an arc suppression coil and a damping resistor which are connected between a bus and the ground in series, the controlled end of the arc suppression coil is connected with the output end of a controller, and the controller adjusts the inductance value of the arc suppression coil according to the capacitance to the ground of the system.

The transfer resistance-adjustable active interference arc extinction device is characterized in that the grounding transformer is a Z-shaped grounding transformer.

The transfer resistance adjustable active intervention arc suppression device is characterized in that the arc suppression coil is a turn-adjusting arc suppression coil, a capacitance-adjusting arc suppression coil, a phase-controlled arc suppression coil, a magnetic control arc suppression coil, a magnetic bias arc suppression coil, a secondary inductance-adjusting arc suppression coil or an arc suppression coil formed by a three-phase five-column transformer and a tuning inductor.

Due to the adoption of the technical scheme, the utility model has the following technical progress.

The utility model can realize phase judgment by adjusting the size of the transfer resistor, and limit short-circuit current when the phase judgment is wrong, thereby effectively avoiding impact damage of heavy current to equipment and power grid; the selection of the grounding line, the identification of the grounding fault exit and the like can be carried out by adjusting the resistance value of the transfer resistor, the accuracy of line selection is improved, the impact on a system generated when the resistance transfer circuit is tentatively exited is reduced, and the safe operation level of the system is effectively improved.

Drawings

Fig. 1 is a system wiring diagram of the present invention.

Wherein: the model JDB.Z grounding transformer, the KL. high-voltage vacuum contactor, the XL. arc suppression coil and the R damping resistor; LH. current transformer, KA.A phase shunt switch, KB.B phase shunt switch, KC.C phase shunt switch, KD. transfer grounding switch, BH. two-phase overcurrent protection device, KZQ controller, R1 first transfer resistor, R2 second transfer resistor and KR. transfer resistor switch; XC. system capacitance to ground, RD. resistance to ground.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

An active intervention arc extinction device with adjustable transfer resistance comprises an arc extinction branch, a fault phase switching branch and a controller KZQ, wherein the arc extinction branch and the fault phase switching branch are arranged between a bus and the ground in parallel, and the arc extinction branch and the fault phase switching branch are respectively connected with the controller.

The utility model discloses well arc extinction branch road's inductance value is the adjustable type, and the arc extinction branch road includes series connection grounding transformer JDB, vacuum high voltage contactor KL, arc suppression coil XL and damping resistance RN between generating line and ground, as shown in FIG. 1. The controlled end of the arc suppression coil XL is connected with the output end of the controller, and the controller adjusts the inductive reactance value of the arc suppression coil according to the capacitive reactance of the system to the ground. The grounding transformer is a Z-shaped grounding transformer JDB, and the arc suppression coil is a turn-adjusting arc suppression coil, a capacitance-adjusting arc suppression coil, a phase-controlled arc suppression coil, a magnetic control arc suppression coil, a magnetic bias arc suppression coil, a secondary inductance-adjusting arc suppression coil or an arc suppression coil formed by a three-phase five-column transformer and tuning inductance.

The fault phase switching branch comprises a switching unit and a resistance transfer circuit; the switching unit comprises three phase shunt switches, namely an A phase shunt switch KA, a B phase shunt switch KB and a C phase shunt switch KC, one ends of the three phase shunt switches KA, KB and KC are respectively connected with phase lines of the bus, the other ends of the three phase shunt switches KB and KC are connected to one end of the resistance transfer circuit in common, and the other end of the resistance transfer circuit is grounded.

The resistance transfer circuit comprises a first transfer resistor R1, a second transfer resistor R2, a transfer grounding switch KD and a transfer resistor switch KR, wherein the second transfer resistor R2 and the transfer resistor switch KR form a series branch circuit and are respectively connected with the transfer grounding switch KD and the first transfer resistor R1 in parallel, as shown in figure 1. In this embodiment, the resistances of the first transfer resistor R1 and the second transfer resistor R2 are equal and both are 50 Ω; but of course may be adjusted to be unequal or other resistances as the case may be.

Controlled ends of three phase shunt switches, a transfer grounding switch KD and a transfer resistance switch KR of the fault phase switching branch circuit are respectively connected with an output end of the controller, and corresponding functions of phase judgment, grounding line selection and grounding disappearance judgment are realized under the instruction of the controller.

The utility model discloses in, current transformer LH has concatenated on the circuit between resistance transfer circuit and the ground, and double-phase over current protection device BH is connected to current transformer LH's output, and double-phase over current protection device BH output is connected with three looks shunt switch's controlled end respectively, and double-phase over current protection device BH is connected with the controller. The current transformer is used for detecting short-circuit current, and when a phase selection error occurs, the two-phase overcurrent protection device controls the grounding phase shunt switch to be tripped, so that the two-phase short-circuit protection effect caused by the phase misjudgment is achieved.

The working principle of the utility model is as follows.

The utility model discloses install transfer earthing switch KD, first transfer resistance R1, second transfer resistance R2 and transfer resistance switch KR in trouble throwing the branch road mutually, through transfer earthing switch KD closed, transfer earthing switch KD disconnection transfer resistance switch KR closed, three kinds of circumstances of transfer earthing switch KD disconnection transfer resistance switch KR disconnection, can realize 0 omega, 25 omega, three kinds of transfer resistance forms of 50 omega.

At the initial phase of grounding judgment, the transfer grounding switch KD is disconnected with the transfer resistance switch KR, and the grounding transfer resistance of the resistance transfer circuit is 50 omega; if the controller determines that the phase is correct, the transfer grounding switch KD is closed, and the device transfers all grounding point current into the device. If the phase selection is wrong, the 50-ohm resistor of the first transfer resistor R1 exists, so that the two-phase short-circuit current is limited to be within 200A, and the impact damage of the large current to equipment and a power grid is effectively avoided; at this time, after the two-phase overcurrent protection device BH detects the short-circuit current, a trip signal is immediately sent to the grounding phase shunt switch, so that the grounding phase shunt switch is tripped, and a two-phase short-circuit protection effect caused by a wrong phase judgment is achieved. The device detects that the phase selection is wrong and carries out the phase selection again until the phase selection is correct.

When the phase is judged correctly, after the grounding phase shunt switch is closed, the grounding loop is transferred to flow through the residual current after the system grounding capacity current and the arc suppression coil inductance current compensation. The transfer grounding switch KD is closed after a certain time delay (which is the action time of two-phase short-circuit protection), so that the grounding current is directly connected to the ground; the controller can selectively disconnect the high-voltage vacuum contactor KL according to the setting, and the arc suppression coil stops running.

If the grounding point current is transferred in the grounding mode, the line selection device does not correctly select the grounding line, the transfer resistance of the resistance transfer circuit can be adjusted to be 25 omega or 50 omega by the device in a mode of switching the transfer grounding switch KD and the transfer resistance switch KR, the impedance of the grounding loop at the side of the device is increased, the shunt current is reduced and the current at a fault point is increased due to the serial connection of the resistance, the circuit with the maximum sudden change amount under the rated phase voltage is converted by comparing the sudden change amount of the zero sequence current of each circuit before and after the change of the transfer resistance and the sudden change amount of the transfer point, and if the numerical values are similar and the directions are opposite, the selected circuit is the grounding line. The specific operation is as follows: and closing the transfer resistor switch KR to enable the first transfer resistor R1 and the second transfer resistor R2 to be connected in parallel, wherein the resistance value of the resistance transfer circuit is 25 omega of the minimum resistance value, and disconnecting the transfer grounding switch KD to enable the 25 omega of the minimum resistance value to be connected in series into the grounding loop.

If the condition is not met, the transfer resistance is continuously increased for comparison until the grounding phase shunt switch is disconnected, so that the transfer resistance is converted into an infinite state (non-transfer state). The specific operation is as follows: disconnecting the transfer resistor switch KR, changing the transfer resistor into 50 omega to be connected in series into a grounding loop, and comparing the mutation quantity of the zero-sequence current of each line; if the grounding circuit can not be selected, the grounding phase shunt switch is disconnected, the transfer resistance is changed into infinite series connection to the grounding circuit, and the sudden change of the zero sequence current of each circuit is compared.

If the line still can not be selected, the controller KZQ sends a locking command to the two-phase over-current protection device BH, the action of the two-phase over-current protection device BH is not allowed, then one of the other two phase shunt switches is grounded, the phase and the ground phase are caused to form a two-phase short circuit through the first grounding resistor R1 and the fault point grounding resistor RD, and the fault grounding line is tripped through the zero sequence current protection of each line. After a certain time delay, the two-phase shunt switch is switched off, and the system recovers to normal operation.

If the system does not recover to the normal state, the line selection is wrong, and the line selection process is repeated.

The utility model discloses still can carry out the judgement that ground connection disappears through the mode of adjusting transfer resistance. In the judging process, the transfer resistance of the resistance transfer circuit is adjusted to be 25 omega or 50 omega by switching the transfer grounding switch KD and the transfer resistance switch KR, if grounding exists, due to the fact that the resistance is connected in series, the impedance of a grounding loop at the side of the device is increased, shunt current is reduced, current at a fault point is increased, the sudden change of the transfer current before and after the change of the transfer resistance when the voltage is converted to a rated phase voltage is judged, if the sudden change is almost 0 or the change of zero-sequence current of each line is not large, the situation that the shunt of the current at the fault point is not realized is judged, and the grounding fault disappears; otherwise the fault is still present.

Certainly, the utility model discloses still except can judging through judging the transfer current abrupt change volume whether ground connection disappears, can also judge through the mode of judging neutral point voltage whether ground connection disappears, if ground connection exists, the equivalent resistance that different ground connection transfer resistance and ground resistance RD connect in parallel and form can be smaller, and neutral point voltage is less, can judge that ground connection still exists; on the contrary, if the grounding is lost, the grounding resistance is infinite, and the neutral point voltage is in the normal value range.

Claims

1. Transfer resistance adjustable initiative intervenes arc extinguishing device, including controller (KZQ) and set up can adjust the arc extinguishing branch road of inductance value in order to realize the arc extinguishing function according to system running state under controller instruction between generating line and ground, its characterized in that: a fault phase switching branch capable of automatically starting and judging phases and transferring grounding current according to the system grounding state is further arranged between the bus and the ground, and the controlled ends of the arc extinction branch and the fault phase switching branch are respectively connected with the output end of the controller; the fault phase switching branch circuit comprises phase shunt switches respectively connected to three phase lines of a bus, the other ends of the three phase shunt switches are connected to one end of a resistance transfer circuit in common, the other end of the resistance transfer circuit is grounded, and the controlled ends of the three phase shunt switches and the resistance transfer circuit are respectively connected with the output end of a controller.

2. The transfer resistance adjustable active intervening arc suppression device of claim 1, wherein: the resistance transfer circuit comprises a transfer grounding switch (KD), a first transfer resistor (R1) and a series branch consisting of a second transfer resistor (R2) and a transfer resistor switch (KR), wherein the transfer grounding switch, the first transfer resistor (R1) and the series branch are connected in parallel, and the three phase shunt switches comprise an A phase shunt switch (KA), a B phase shunt switch (KB) and a C phase shunt switch (KC); the controlled ends of the transfer grounding switch (KD) and the transfer resistance switch (KR) are respectively connected with the output end of the controller.

3. The transfer resistance adjustable active interference arc suppression device according to claim 2, characterized in that: the first transfer resistor (R1) and the second transfer resistor (R2) are equal in resistance and are both 50 omega.

4. The transfer resistance adjustable active interference arc suppression device according to claim 2, characterized in that: the circuit between the resistance transfer circuit and the ground is connected with a current transformer (LH) in series, the output end of the current transformer (LH) is connected with a two-phase overcurrent protection device (BH), the output end of the two-phase overcurrent protection device (BH) is respectively connected with the controlled ends of the three-phase shunt switches, and the two-phase overcurrent protection device (BH) is connected with a controller (KZQ).

5. The transfer resistance adjustable active intervening arc suppression device of claim 1, wherein: the arc extinction branch road is including series connection at grounding transformer (JDB) between generating line and the ground, vacuum high voltage contactor (KL), arc extinction coil (XL) and damping resistance (R), and the controlled end connection director's of arc extinction coil (XL) output, the controller is according to the inductance value that the system held the regulation arc extinction coil to ground.

6. The transfer resistance adjustable active interference arc suppression device according to claim 5, characterized in that: the grounding transformer is a Z-type grounding transformer (JDB).

7. The transfer resistance adjustable active interference arc suppression device according to claim 5, characterized in that: the arc suppression coil is a turn-adjusting arc suppression coil, a capacitance-adjusting arc suppression coil, a phase-control arc suppression coil, a magnetic bias arc suppression coil, a secondary inductance-adjusting arc suppression coil or an arc suppression coil formed by a three-phase five-column transformer and a tuning inductor.