Control device for delaying input of three-phase compensation capacitor and three-phase compensation capacitor device

Abstract

The utility model relates to a control device for delaying input of a three-phase compensation capacitor and a three-phase compensation capacitor device, and belongs to the field of reactive compensation of an electric power system. The control device comprises: a voltage detection module, which is used for outputting a power-on control signal after power grid line fault trip-out coincidence succeeds or a power grid line is powered on; the normally-open node of the time relay is closed in a delayed manner when a power-on control signal exists, and the normally-open node of the time relay is used for controlling the three-phase compensation capacitor to be put into a power grid line. According to the utility model, the overvoltage damage to the three-phase compensation capacitor caused by the transient fault trip-out reclosing success of the power grid line or the superposed voltage after the power grid line is electrified can be reduced, and the service life of the three-phase compensation capacitor is prolonged. Meanwhile, the control device is simple in structure, easy to implement, high in reliability and universal.

Description

TECHNICAL FIELD

[0001] The utility model relates to a control device for delaying three -phase compensation capacitor input and three -phase compensation capacitor device belong to electric power system reactive compensation field. BACKGROUND

[0002] Most of the power equipment in the power grid works according to the principle of electromagnetic induction, and they establish an alternating magnetic field in the energy conversion process, and the power absorbed and released in a cycle is equal. When the power energy passes through a pure inductor or a pure capacitor circuit, there is no energy consumption, and only the reciprocal exchange between the load and the power supply, since this exchange power does not do work outside, it is called reactive power. Reactive power reflects the internal and external exchange energy situation, it does not represent the average power done in unit time like active power, but it is essential to maintain the stability of the power system, ensure power quality and safe operation.

[0003] If the reactive power in the power grid is insufficient, the end voltage of the equipment will drop, and the normal work of the power equipment under the rated technical parameters cannot be guaranteed, thereby affecting the normal work of the power equipment. In the existing power system, three-phase compensation capacitors are usually used for reactive power compensation.

[0004] However, when the power grid line trips and successfully recloses, or the three-phase compensation capacitor is directly put into the power grid line after power-on, the three-phase compensation capacitor will bear superimposed voltage, resulting in overvoltage damage. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a control device for delaying the switching of capacitors and switching capacitors to solve the problem of damage to three-phase compensation capacitors in the prior art due to bearing superimposed voltage after the reclosing of the power grid line after instantaneous fault tripping or the power-on of the power grid line.

[0006] To achieve the above-mentioned purpose, the utility model provides the following scheme:

[0007] The utility model relates to a control device for delaying three -phase compensation capacitor input, including: the voltage detection module for outputting the incoming call control signal after the power grid line fault tripping reclosing success or the power grid line power-on;Further include the time relay of the normally open node delay closure when having incoming call control signal, the normally open node of time relay is used for controlling three -phase compensation capacitor input power grid line.

[0008] Further, it further includes an intermediate relay.

[0009] The coil of the intermediate relay is energized when the incoming call control signal is received; the normally open node of the intermediate relay is connected in series with the control end of the time relay to form a loop.

[0010] Further, the voltage detection module comprises an AND gate module and three voltage conversion modules connected with the three phases in the power grid line respectively;

[0011] The voltage conversion module is used for converting the alternating current of the corresponding phase into direct current; the output ends of the three voltage conversion modules are connected with the input ends of the AND gate module, and the output end of the AND gate module is connected with the coil of the intermediate relay.

[0012] The AND gate module is used for outputting the incoming call control signal when the voltages output by the three voltage conversion modules are all within the preset voltage range.

[0013] Further, the control relay is further included.

[0014] The coil of the control relay is connected in series with the normally open node of the time relay to form a loop, and the normally open node of the control relay is connected in series between the three-phase compensation capacitor and the three-phase live wire in the power grid line.

[0015] Further, the air switch for short-circuit protection of the three-phase compensation capacitor is connected in series between the normally open node of the control relay and the three-phase live wire in the power grid line.

[0016] Further, the reactor for suppressing the surge voltage and current is connected in series between the normally open node of the control relay and the three-phase compensation capacitor.

[0017] Further, the display module for displaying the residual delay time is further included.

[0018] Further, the alarm module for alarming when the internal fault or abnormality of the time relay occurs is further included.

[0019] The utility model discloses a kind of three-phase compensation capacitor devices, including the three-phase compensation capacitor of triangular connection and as described in preceding for delaying the control device of three-phase compensation capacitor input.

[0020] The utility model discloses beneficial effect is: as the pioneering invention creation, the utility model provides a kind of control device and three-phase compensation capacitor device for delaying three-phase compensation capacitor input, voltage detection module is used to detect the voltage situation on power grid line, can be in real time the situation of power grid line;After power grid line fault tripping reclosing success or power grid line energization, voltage detection module exports incoming call control signal;When there is incoming call control signal, the normally open node of time relay delays closing, controls three-phase compensation capacitor delay input power grid line after closing. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is the structure schematic diagram of a kind of control device for delaying three-phase compensation capacitor input provided by the utility model embodiment;

[0022] Figure 2 It is the connection relationship schematic diagram of voltage detection module and intermediate relay connection provided by the utility model embodiment;

[0023] Figure 3 It is the connection relationship schematic diagram of time relay and control relay connection provided by the utility model embodiment;

[0024] Figure 4 It is the connection relationship schematic diagram of control relay and three-phase compensation capacitor connection provided by the utility model embodiment. DETAILED DESCRIPTION

[0025] To make the purpose, technical scheme and advantage of the utility model more clear and apparent, below, connecting with drawing and embodiment, the utility model is further explained in detail.

[0026] The utility model discloses the conception is in: through setting time relay, so that after power grid line transient fault tripping reclosing success or power grid line energization, three-phase compensation capacitor delays a period of time and then input power grid and work normally.

[0027] Specifically, voltage detection module is used to detect the voltage situation on power grid line, can be in real time the situation of power grid line;After power grid line fault tripping reclosing success or power grid line energization, voltage detection module exports incoming call control signal;When there is incoming call control signal, the normally open node of time relay delays closing, controls three-phase compensation capacitor delay input power grid line after closing.

[0028] An embodiment of a kind of control device for delaying three-phase compensation capacitor input:

[0029] Figure 1 The control device for delaying three-phase compensation capacitor input provided by the embodiment of the utility model is a kind of structure schematic diagram, it includes: the voltage detection module 10 for output incoming call control signal after power grid line fault trip reclosing success or power grid line energization;Further include the time relay KT of normally open node delay closure when there is incoming call control signal, the normally open node of time relay KT is used to control three-phase compensation capacitor 60 input power grid line.

[0030] Wherein, power grid line fault trip reclosing success refers to the reclosing device automatically closes the disconnected circuit breaker after the fault in line causes circuit breaker to trip, and this time closing operation is successful, so as to restore the normal operation of transmission line.It is specifically described that when power grid line appears fault, such as the fault caused by instantaneous lightning, wind damage, bird damage, etc., the relay protection device will act quickly, and circuit breaker trips, and cuts off fault line.At this time, if the fault is instantaneous, then after the line is disconnected, the insulation performance of fault point can be restored.At this time, reclosing device will automatically close circuit breaker again in a short time (generally 0.15~0.5 seconds), to try to restore power supply.If reclosing is successful, then line restores normal operation, reduces power-off time, and improves the reliability of power supply;Power grid line energization refers to the situation that power grid line is re-powered after power-off.

[0031] As an optional implementation, the control device for delaying capacitor switching provided by the embodiment of the utility model can further include intermediate relay KC.

[0032] The coil 70A of intermediate relay KC is powered when there is incoming call control signal;Normally open node 70B of intermediate relay KC and control end of time relay KT are connected in series to form a loop.

[0033] As an optional implementation, the control device for delaying capacitor switching provided by the embodiment of the utility model can further include control relay KM.

[0034] The coil 30A of control relay KM and normally open node 20B of time relay KT are connected in series to form a loop, and normally open node 30B of control relay KM is connected in series between three-phase compensation capacitor 60 and three-phase firewire in power grid line.

[0035] In order to reduce the phenomenon of damage to three-phase compensation capacitor 60 caused by short circuit, as an optional implementation, the control device for delaying capacitor switching provided by the embodiment of the utility model can further include three air switches.Three air switches are connected in series on the line between normally open node of control relay KM and three-phase firewire in power grid line.

[0036] In order to reduce the occurrence of the phenomenon that the inrush voltage and current cause damage to the three-phase compensation capacitor 60, as an optional implementation, the control device for delaying the switching of the capacitor provided by the embodiment of the utility model can further comprise three reactors. The three reactors are respectively connected in series on the line between the normally open node of the control relay KM and the three-phase compensation capacitor 60.

[0037] The connection relationship between the voltage detection module 10 and the intermediate relay KC will be described in detail below. Figure 2 The connection relationship between the voltage detection module 10 and the intermediate relay KC will be described in detail below.

[0038] Figure 2 is a connection relationship diagram of the connection between the voltage detection module and the intermediate relay provided by the embodiment of the utility model, as shown in Figure 2 The voltage detection module 10 comprises: a first voltage conversion module 101A, a second voltage conversion module 101B, a third voltage conversion module 101C, and an AND gate module 102. The intermediate relay KC comprises a coil 70A and a normally open node 70B (not shown).

[0039] Specifically, one end of the first voltage conversion module 101A is connected to the A-phase live wire in the power grid line, and the other end is connected to the input end of the AND gate module 102; one end of the second voltage conversion module 101B is connected to the B-phase live wire in the power grid line, and the other end is connected to the input end of the AND gate module 102; one end of the third voltage conversion module 101C is connected to the C-phase live wire in the power grid line, and the other end is connected to the input end of the AND gate module 102; the output end of the AND gate module 102 is connected to the coil 70A of the intermediate relay KC.

[0040] It can be understood that the connection relationship between the three voltage conversion modules and the three-phase live wire in the power grid line can be changed, for example, one end of the first voltage conversion module 101A can be connected to the B-phase live wire, one end of the second voltage conversion module 101B can be connected to the A-phase live wire, and one end of the third voltage conversion module 101C can be connected to the C-phase live wire; for another example, one end of the first voltage conversion module 101A can be connected to the C-phase live wire, one end of the second voltage conversion module 101B can be connected to the B-phase live wire, and one end of the third voltage conversion module 101C can be connected to the A-phase live wire, and so on, which is not particularly limited by the utility model, as long as the three voltage conversion modules are connected to live wires of different phases. Subsequently, the first voltage conversion module 101A is connected to the A-phase live wire in the power grid line, the second voltage conversion module 101B is connected to the B-phase live wire in the power grid line, and the third voltage conversion module 101C is connected to the C-phase live wire in the power grid line.

[0041] The first voltage conversion module 101A, the second voltage conversion module 101B and the third voltage conversion module 101C each include a control loop and an alternating current loop, the control loop is a direct current loop and has stable control performance; and the main loop is an alternating current loop and can adapt to actual operation requirements of a power system to provide reliable power supply guarantee for the whole device. The first voltage conversion module 101A, the second voltage conversion module 101B and the third voltage conversion module 101C are each used for converting alternating current of a corresponding phase into direct current. For example, when the first voltage conversion module 101A is connected to the A-phase live wire in a power grid line, the second voltage conversion module 101B is connected to the B-phase live wire in the power grid line, and the third voltage conversion module 101C is connected to the C-phase live wire in the power grid line, the first voltage conversion module 101A is used for converting alternating current of the A-phase into direct current; the second voltage conversion module 101B is used for converting alternating current of the B-phase into direct current; and the third voltage conversion module 101C is used for converting alternating current of the C-phase into direct current.

[0042] The AND gate module 102 is used for outputting a power-on control signal when the voltages output by the three voltage conversion modules are all within a preset voltage range, and is also used for outputting a cut-off control signal when the voltages output by the three voltage conversion modules have one phase not within the preset voltage range. The coil 70A of the intermediate relay KM is electrified when the power-on control signal is present, and is de-energized when the cut-off control signal is present.

[0043] The preset voltage range can be a set voltage range, which can be higher than a normal voltage range or lower than the normal voltage range; the preset voltage range can also be the normal voltage range, and the utility model does not specially limit this. In the following, the preset voltage range is taken as the normal voltage range for example, and example description is made.

[0044] The following will be described in combination with Figure 3 The connection relationship between the time relay KT and the control relay KM will be described in detail.

[0045] Figure 3 is a connection relationship schematic diagram of a time relay and a control relay provided by an embodiment of the utility model, as Figure 3 shown, the time relay KT includes a control end 20A and a normally open node 20B, and the control relay KM includes a coil 30A and three groups of normally open nodes (not shown).

[0046] Specifically, one end of the control end 20A of the time relay KT is connected to any phase live wire L in the power grid circuit through the normally open node 70B of the intermediate relay KC, and the other end of the control end 20A of the time relay KT is connected to the zero line N in the power grid circuit; one end of the normally open node 20B of the time relay KT is connected to any phase live wire L in the power grid circuit, and the other end of the normally open node 20B of the time relay KT is connected to the zero line N in the power grid circuit through the coil 30A of the control relay KM.

[0047] The normally open node 20B of the time relay KT and the normally open node 70B of the intermediate relay KC can be connected to the same live wire or different live wires, and the utility model does not make special limitation on this. The utility model embodiment takes the normally open node 20B of the time relay KT and the normally open node 70B of the intermediate relay KC being connected to the same live wire as an example for example description.

[0048] The control end of the time relay KT is used to control the coil of the time relay KT to be powered on according to a preset delay time after the normally open node 70B of the intermediate relay KC is closed; and the coil 30A of the control relay KM is used to be powered on after the normally open node 20B of the time relay KT is closed.

[0049] The time relay KT has high-precision timing function, can rapidly and accurately start a delay program after receiving the incoming call control signal output from the voltage detection module 10, delay according to a preset delay time, and the control end 20A of the time relay KT controls the coil of the time relay KT to be powered on and the normally open node 20B of the time relay KT to be closed after the delay time ends. During the delay process, the time relay KT continuously monitors the stability of the input signal, and ensures that the control relay KM is only sent to send an input instruction for the three-phase compensation capacitor to be input into the power grid circuit when the power grid voltage is in a stable state and in a preset voltage range.

[0050] The preset delay time can be flexibly set according to different power grid operation scenes and actual demands, and the range can be from several seconds to several minutes.

[0051] In order to facilitate the operating personnel to know the running state of the time relay KT at any time, as an optional implementation manner, the utility model embodiment further comprises a display module (not shown) for displaying the remaining time of the preset delay time. The display module can be a liquid crystal display screen, and through the numbers on the liquid crystal display screen, the operating personnel can know how long the preset delay time will end.

[0052] In order to facilitate maintenance personnel to carry out quick maintenance and maintenance, guarantee the reliable operation of time relay KT, as an optional implementation, the control device for delaying the switching of the capacitor further comprises an alarm module for alarming when a fault or an anomaly occurs in the control device.

[0053] The connection relationship between the control relay KM and the three-phase compensation capacitor 60 will be described below. Figure 4

[0054] Figure 4 is a connection relationship diagram of the control relay and the three-phase compensation capacitor provided by the utility model, as shown in Figure 4 The normally open nodes of the control relay KM include three groups, which are a first group of normally open nodes 30B1, a second group of normally open nodes 30B2 and a third group of normally open nodes 30B3.

[0055] One end of the first group of normally open nodes 30B1 is connected to the A-phase live wire in the power grid circuit, and the other end is connected to the corner point a of the three-phase compensation capacitor; one end of the second group of normally open nodes 30B2 is connected to the B-phase live wire in the power grid circuit, and the other end is connected to the corner point b of the three-phase compensation capacitor; one end of the third group of normally open nodes 30B3 is connected to the C-phase live wire in the power grid circuit, and the other end is connected to the corner point c of the three-phase compensation capacitor.

[0056] The three groups of normally open nodes of the control relay KM are used to control the three-phase compensation capacitor to be put into the power grid circuit; the three groups of normally open nodes of the control relay KM are also used to be disconnected when a fault occurs in the power grid circuit, so as to control the three-phase compensation capacitor to be cut out of the power grid.

[0057] The three-phase compensation capacitor is connected in a delta connection.

[0058] It can be understood that the connection relationship between the three groups of normally open nodes and the three-phase live wires in the power grid circuit can be changed, for example, one end of the first group of normally open nodes 30B1 is connected to the B-phase live wire in the power grid circuit, one end of the second group of normally open nodes 30B2 is connected to the A-phase live wire in the power grid circuit, and one end of the third group of normally open nodes 30B3 is connected to the C-phase live wire in the power grid circuit; for example, one end of the first group of normally open nodes 30B1 is connected to the C-phase live wire in the power grid circuit, one end of the second group of normally open nodes 30B2 is connected to the B-phase live wire in the power grid circuit, and one end of the third group of normally open nodes 30B3 is connected to the A-phase live wire in the power grid circuit, and the like, which are not particularly limited in the utility model, as long as the three groups of normally open nodes are connected to different three-phase live wires. The first end of the first group of normally open nodes 30B1 is connected to the A-phase live wire in the power grid circuit, the first end of the second group of normally open nodes 30B2 is connected to the B-phase live wire in the power grid circuit, and the first end of the third group of normally open nodes 30B3 is connected to the C-phase live wire in the power grid circuit.​

[0059] It can be understood that the connection relationship between the three groups of normally open nodes and the three-phase compensation capacitor can be changed, for example, the other end of the first group of normally open nodes 30B1 is connected to the corner point b of the three-phase compensation capacitor, the other end of the second group of normally open nodes 30B2 is connected to the corner point a of the three-phase compensation capacitor, and the other end of the third group of normally open nodes 30B3 is connected to the corner point c of the three-phase compensation capacitor; for example, the other end of the first group of normally open nodes 30B1 is connected to the corner point c of the three-phase compensation capacitor, the other end of the second group of normally open nodes 30B2 is connected to the corner point b of the three-phase compensation capacitor, and the other end of the third group of normally open nodes 30B3 is connected to the corner point a of the three-phase compensation capacitor, and the like, and the present application does not particularly limit this, as long as the three groups of normally open nodes are connected to the three non-corner points of the three-phase compensation capacitor. In the following, the other end of the first group of normally open nodes 30B1 is connected to the corner point a of the three-phase compensation capacitor, the other end of the second group of normally open nodes 30B2 is connected to the corner point b of the three-phase compensation capacitor, and the other end of the third group of normally open nodes 30B3 is connected to the corner point c of the three-phase compensation capacitor, which is taken as an example for exemplary description.

[0060] Among them, in order to reduce the damage to the three-phase compensation capacitor 60 due to short circuit, three air switches are added, and the connection relationship between the three-phase compensation capacitor 60 is that: the first air switch 40A is connected in series on the connection line between the first group of normally open nodes 30B1 and the A-phase live wire; the second air switch 40B is connected in series on the connection line between the second group of normally open nodes 30B2 and the B-phase live wire; the third air switch 40C is connected in series on the connection line between the third group of normally open nodes 30B3 and the C-phase live wire.

[0061] Among them, the first air switch 40A, the second air switch 40B and the third air switch 40C are manually closed by maintenance personnel, and when a short circuit occurs on the corresponding line, the air switch on the corresponding line will be automatically disconnected.

[0062] Among them, in order to reduce the damage to the three-phase compensation capacitor 60 caused by surge voltage and current, three reactors are added, and the connection relationship between the three-phase compensation capacitor 60 is that: the first reactor 50A is connected in series on the connection line between the first group of normally open nodes 30B1 and the corner point a of the three-phase compensation capacitor 60; the second reactor 50B is connected in series on the connection line between the second group of normally open nodes 30B2 and the corner point b of the three-phase compensation capacitor 60; the third reactor 50C is connected in series on the connection line between the third group of normally open nodes 30B3 and the corner point c of the three-phase compensation capacitor 60.

[0063] The working principle of the control device for delaying the input of the three-phase compensation capacitor provided by the embodiment of the present application will be described below. Figures 1-4

[0064] ​The maintenance personnel manually close the first air switch 40A, the second air switch 40B and the third air switch 40C. In the power grid circuit, when the voltage of one phase of the three-phase power is not in the preset voltage range (i.e. the power grid circuit is faulty), the AND gate module 102 outputs a cut-off indication signal, the coil 70A of the intermediate relay KC loses power, the normally open node 70B of the intermediate relay KC is disconnected, and the intermediate relay KC is in an open state. The time relay KT is disabled, the coil 30A of the control relay KM loses power, and the normally open nodes of the control relay KM (i.e. the first group of normally open nodes 30B1, the second group of normally open nodes 30B2 and the third group of normally open nodes 30B3) are disconnected. Since all three groups of normally open nodes of the control relay KM are disconnected, the three-phase compensation capacitor is cut off from the power grid circuit, and the three-phase compensation capacitor stops working.

[0065] After the power grid circuit is tripped and reclosed or the power grid circuit is powered on, and the three-phase voltage of the power grid circuit is all in the preset voltage range, the AND gate module 102 outputs an incoming call control signal, the coil 70A of the intermediate relay KC is powered on, the normally open node 70B of the intermediate relay KC is closed, and the intermediate relay KC is in a closed state. When the intermediate relay KC is in a closed state, the time relay KT starts to delay according to the preset delay time, and after the preset delay time ends, the control end 20A of the time relay KT controls the coil of the time relay KT to be powered on, the normally open node 20B of the time relay KT is attracted, and the time relay KT is in a closed state. When the time relay KT is in a closed state, the coil 30A of the control relay KM is powered on, and the three groups of normally open contacts of the control relay KM (i.e. the first group of normally open contacts 30B1, the second group of normally open contacts 30B2 and the third group of normally open contacts 30B3) are all attracted, and the control relay KM is in a closed state. When the control relay KM is in a closed state, the three-phase compensation capacitor is put into the power grid circuit and starts to work.

[0066] After the three-phase compensation capacitor is put into the power grid circuit and starts to work, if a short circuit occurs in the three-phase power, the air switch on the firewire line will be disconnected, and the three-phase compensation capacitor will stop working.

[0067] The utility model embodiment provides a kind of control device for delaying three-phase compensation capacitor input, comprising: the voltage detection module for outputting incoming call control signal after power grid line fault tripping reclosing success or power grid line energization;Further include the time relay of normally open node delay closure when there is incoming call control signal, the normally open node of time relay is used to control three-phase compensation capacitor input power grid line.By using voltage detection module to detect the voltage condition on power grid line, the condition of power grid line can be mastered in real time;After power grid line fault tripping reclosing success or power grid line energization, voltage detection module outputs incoming call control signal;The normally open node of time relay is delayed closed when there is incoming call control signal, controls three-phase compensation capacitor delay input power grid line after closure.It can reduce the overvoltage damage of superimposed voltage to three-phase compensation capacitor after power grid line transient fault tripping reclosing success or power grid line energization, improve the service life of three-phase compensation capacitor.Simultaneously, the control device structure is simple, easy to realize, and high reliability, with universality.

[0068] An embodiment of a three-phase compensation capacitor device:

[0069] The utility model embodiment provides a kind of three-phase compensation capacitor device, comprising: including the three-phase compensation capacitor of delta connection and as described in preceding for delaying three-phase compensation capacitor input control device.

[0070] Wherein, for the detailed description of control device can refer to the relevant description of control device in preceding "a kind of control device for delaying three-phase compensation capacitor input", this place will not be repeated.

[0071] The utility model embodiment provides a kind of three-phase compensation capacitor device: by using voltage detection module to detect the voltage condition on power grid line, the condition of power grid line can be mastered in real time;After power grid line fault tripping reclosing success or power grid line energization, voltage detection module outputs incoming call control signal;The normally open node of time relay is delayed closed when there is incoming call control signal, controls three-phase compensation capacitor delay input power grid line after closure.It can reduce the overvoltage damage of superimposed voltage to three-phase compensation capacitor after power grid line transient fault tripping reclosing success or power grid line energization, improve the service life of three-phase compensation capacitor.Simultaneously, three-phase compensation capacitor device structure is simple, easy to realize, and high reliability, with universality.

Claims

1. A control device for delaying the input of a three-phase compensation capacitance, characterized by include: A voltage detection module is used to output a power supply control signal after a power grid line fault trip and reclosing is successful or after the power grid line is energized; it also includes a time relay that delays closing a normally open node when the power supply control signal is received, wherein the normally open node of the time relay is used to control the three-phase compensation capacitor to be connected to the power grid line.

2. The control device for delaying the input of three-phase compensation capacitance according to claim 1, characterized by, It also includes intermediate relays; The coil of the intermediate relay is energized when the incoming power control signal is received; the normally open terminal of the intermediate relay is connected in series with the control terminal of the time relay to form a circuit.

3. The control device for delaying the input of three-phase compensation capacitance according to claim 2, characterized by, The voltage detection module includes an AND gate module and three voltage conversion modules respectively connected to three phases of the power grid line; The voltage conversion module is used to convert the alternating current of the corresponding phase into direct current; The outputs of the three voltage conversion modules are connected to the input of the AND gate module, and the output of the AND gate module is connected to the coil of the intermediate relay. The AND gate module is used to output the incoming call control signal when the voltages output by the three voltage conversion modules are all within a preset voltage range.

4. The control device for delaying the input of three-phase compensation capacitance according to claim 1, characterized by, It also includes control relays; The coil of the control relay is connected in series with the normally open terminal of the time relay to form a circuit. The normally open terminal of the control relay is connected in series between the three-phase compensation capacitor and the three-phase live wires in the power grid line.

5. The control device for delaying the input of three-phase compensation capacitance according to claim 4, characterized by, An air switch for short-circuit protection of the three-phase compensation capacitor is connected in series on the line between the normally open node of the control relay and the three-phase live wires in the power grid line.

6. The control device for delaying the input of three-phase compensation capacitance according to claim 4 or 5, characterized by, A reactor for suppressing surge voltage and current is connected in series on the line between the normally open terminal of the control relay and the three-phase compensation capacitor.

7. The control device for delaying the input of three-phase compensation capacitance according to claim 1, characterized by, Also includes: A display module used to show the remaining delay time.

8. The control device for delaying the input of three-phase compensation capacitance according to claim 1, characterized by, Also includes: An alarm module for triggering an alarm when a fault or abnormality occurs inside the time relay.

9. A three-phase compensation capacitance device, characterized by It includes a three-phase compensation capacitor connected in a delta configuration and a control device for delaying the connection of the three-phase compensation capacitor as described in any one of claims 1-8.

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