Improved microcontrollable fixed series compensation device with overcurrent protection

Abstract

The application discloses an improved micro-controllable fixed series compensation device with over-current protection, which comprises a general fixed series capacitor compensation device C, an inductor group adjusting circuit and an over-current protection circuit connected in series, and disconnecting switches G8 connected in parallel at both ends of the micro-controllable fixed series compensation device; the incoming line end of the general fixed series capacitor compensation device C in the micro-controllable fixed series compensation device is connected with the incoming line end A of a power distribution cabinet through the disconnecting switch G1; and the outgoing line end of the over-current protection circuit in the micro-controllable fixed series compensation device is connected with the outgoing line end B of the power distribution cabinet through the disconnecting switch G9. The capacitor group originally used for compensating general inductive loads is designed as the inductor group which can be dynamically adjusted, so that the fixed series capacitor compensation device can be applied to the special load field for adjustment and disconnected when the power grid recovers the general load, and the fixed series capacitor compensation device is connected to the power grid.

Description

Technical Field

[0001] This invention belongs to the field of power systems, and specifically relates to an improved micro-controllable fixed series compensation device with overcurrent protection. Background Technology

[0002] With the depletion of fossil fuels and the increasing cost of extraction, coupled with the growing global climate problems caused by excessive greenhouse gas emissions, the automotive industry, which relies heavily on fossil fuels, is forced to undergo reform. The new energy electric vehicle industry, in particular, has experienced significant growth in recent years. Consequently, the charging demand for new energy vehicles is increasing, and its impact on the entire power grid system will become increasingly apparent. In particular, peak demand for vehicle charging may significantly affect the overall grid capacity.

[0003] Currently, high-power DC charging stations for electric vehicles mainly utilize power electronics technology and nonlinear devices such as electronic rectifiers for charging. In actual use, this inevitably generates harmonics and reactive currents, thus affecting power quality. Each electrical device has its own rated voltage value; operating at the rated voltage ensures its lifespan. However, when the distribution network voltage deviates, the network operates under non-rated voltage, thus deviating from its optimal electrical state. Prolonged operation of devices in this state significantly reduces safety and reliability. Furthermore, with the large-scale connection of electric vehicle charging stations to the grid, the grid load will increase sharply during peak charging periods, leading to voltage drops. This not only reduces grid stability but also increases grid losses to some extent, potentially causing various safety accidents. In addition, some electric vehicle charging stations have high-power fast charging capabilities, which also significantly impact the power quality of the distribution network.

[0004] Series capacitor compensation devices utilize the inductive characteristic of transmission lines in a power transmission system. Large-capacity capacitors, exhibiting capacitive behavior, are connected in series with the transmission line to compensate for the inductive reactance, shorten the equivalent electrical distance of the line, and reduce the voltage drop and phase angle difference between the sending and receiving busbars. This increases transmission capacity, reduces transmission line losses, and improves system stability. Compared with other compensation schemes, series capacitor compensation devices require less investment, offer good economic efficiency, and have significant regulation capabilities, thus finding widespread application in power systems both domestically and internationally.

[0005] With the rapid development of electric vehicles, a large number of capacitive loads are generated during peak charging times, causing grid structure disorder and reduced transmission efficiency (i.e., special load areas). Current controllable series compensation devices can only regulate general inductive loads. When special loads occur, i.e., large capacitive loads, their inductive regulation tools are limited by the angle of the anti-parallel thyristors, resulting in a very limited adjustment range and an inability to effectively regulate the grid. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an improved micro-controllable fixed series compensation device with overcurrent protection. The capacitor bank, originally designed for compensating general inductive loads, is redesigned as a dynamically adjustable inductor bank. This allows for adjustment in special load applications and disconnection when the grid returns to normal load conditions, enabling the fixed series capacitor compensation device to connect to the grid. With micro-adjustment capabilities, this novel series compensation device can adjust the capacitive reactance value and also incorporate a small amount of inductive reactance for specific load conditions, meeting the needs of both normal line operation and fault conditions.

[0007] The main technical solution adopted in this invention is as follows:

[0008] An improved micro-controllable fixed series compensation device with overcurrent protection includes a general fixed series capacitor compensation device C, an inductor group adjustment circuit, and an overcurrent protection circuit. The general fixed series capacitor compensation device C, the inductor group adjustment circuit, and the overcurrent protection circuit are connected in series to form the micro-controllable fixed series compensation device. A disconnecting switch G8 is connected in parallel across the two ends of the micro-controllable fixed series compensation device. The input terminal of the general fixed series capacitor compensation device C is connected to the input terminal A of the distribution cabinet via a disconnecting switch G1. The output terminal of the overcurrent protection circuit in the micro-controllable fixed series compensation device is connected to the output terminal B of the distribution cabinet via a disconnecting switch G9.

[0009] Preferably, the general fixed series capacitor compensation device C includes a series capacitor bank C, a first overvoltage protection device, a variable resistor MOV1, and a disconnect switch G2. The first overvoltage protection device, the variable resistor MOV1, and the disconnect switch G2 are connected in parallel with the series capacitor bank C. The series capacitor bank C includes a disconnect switch G3, a disconnect switch G4, and the series capacitor bank C. The disconnect switches G3 and G4 are connected in series at both ends of the series capacitor bank C. The disconnect switch G3 is connected to the disconnect switch G1, and the disconnect switch G4 is connected to the input terminal of the inductor group adjustment circuit.

[0010] Preferably, the inductor group adjustment circuit includes a series-parallel inductor group, a second overvoltage protection device, a variable resistor MOV2, and a disconnecting switch G6. The input terminal of the series-parallel inductor group is connected to the disconnecting switch G4 via the disconnecting switch G5, and the output terminal of the series-parallel inductor group is connected to the input terminal of the overcurrent protection circuit via the disconnecting switch G7. The second overvoltage protection device, the variable resistor MOV2, and the disconnecting switch G6 are connected in parallel with the series-parallel inductor group, and the disconnecting switch G6 is connected in series with the current limiter Q.

[0011] Preferably, the series-parallel inductor group includes M series inductor elements LM, where M = 1, 2, 3... M, N parallel inductor elements LN', where N = 1, 2, 3... N, N series circuit breakers KN', where N = 1, 2, 3... N, and M parallel circuit breakers KM, where M = 1, 2, 3... M. The M series inductor elements LM are connected in series sequentially, and each series inductor element LM is connected in parallel to a corresponding parallel circuit breaker KM. The N parallel inductor elements LN' are connected in parallel across the series circuit of the M series inductor elements LM, and each parallel inductor element LN' is connected in series to a corresponding series circuit breaker KN', thus forming a series-parallel inductor group.

[0012] Preferably, both the rheostats MOV1 and MOV2 are zinc oxide rheostats.

[0013] Preferably, the first voltage protection device includes a spark gap GAP, a circuit breaker Kc, and a damping device RL, wherein the spark gap GAP and the circuit breaker Kc are connected in parallel and then connected in series with the damping device RL.

[0014] Preferably, the first voltage protection device includes a spark gap GAP and a circuit breaker K. L and damping device RL, wherein the spark gap GAP and circuit breaker K L They are connected in parallel and then connected in series with the damping device RL.

[0015] Preferably, the overcurrent protection circuit includes a circuit breaker K and an overcurrent reactor L connected in parallel. The input terminal of the overcurrent protection circuit is connected to a disconnecting switch G7, and the output terminal is connected to the output terminal B of the distribution cabinet via a disconnecting switch G9.

[0016] Preferably, all of the disconnecting switches are high-speed eddy current switches.

[0017] Preferably, all circuit breakers are vacuum arc-extinguishing circuit breakers.

[0018] Beneficial effects: This invention provides an improved micro-controllable fixed series compensation device with overcurrent protection, which has the following advantages:

[0019] (1) The circuit of the present invention is simple, safe and reliable. It can limit the intensity of short-circuit current during short circuit and compensate the distributed inductive reactance of the circuit by compensating the series capacitor bank C.

[0020] (2) The present invention can moderately adjust the large amount of capacitive reactance during peak power consumption for special application occasions, thereby improving the stability of the power system and improving the voltage quality of the line;

[0021] (3) The present invention can increase the power transmission distance and increase the transmission capacity, improve the comprehensive utilization rate of electrical energy, and realize power outage maintenance or replacement of internal components through disconnecting switches G1, G8 and G9, which greatly improves the reliability and safety of power supply, while avoiding economic losses caused by power outage maintenance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the circuit structure of Example 1;

[0023] Figure 2 This is a circuit diagram of the inductor group adjustment circuit of the present invention;

[0024] Figure 3 This is a circuit diagram of the general fixed series capacitor compensation device C of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0026] Example 1

[0027] An improved micro-controllable fixed series compensation device with overcurrent protection, such as... Figure 1 As shown, the device includes a general fixed series capacitor compensation device C, an inductor group adjustment circuit, and an overcurrent protection circuit. The general fixed series capacitor compensation device C, the inductor group adjustment circuit, and the overcurrent protection circuit are connected in series to form a micro-controllable fixed series compensation device. A disconnecting switch G8 is connected in parallel across both ends of the micro-controllable fixed series compensation device. The disconnecting switch G8 controls the connection and disconnection of the entire micro-controllable fixed series compensation device. The input terminal of the general fixed series capacitor compensation device C is connected to the input terminal A of the distribution cabinet via a disconnecting switch G1. The output terminal of the overcurrent protection circuit in the micro-controllable fixed series compensation device is connected to the output terminal B of the distribution cabinet. In this embodiment 1, power outage maintenance or replacement of components within the device is achieved through disconnecting switches G1, G8, and G9.

[0028] like Figure 2As shown, a typical fixed series capacitor compensation device C includes a series capacitor bank C, a first overvoltage protection device, a variable resistor MOV1, and a disconnecting switch G2. The first overvoltage protection device, the zinc oxide MOV1 (non-linear resistor), and the disconnecting switch G2 are connected in parallel with the series capacitor bank C. The series capacitor bank C includes disconnecting switches G3 and G4, and the disconnecting switches G3 and G4 are connected in series across the two ends of the series capacitor bank C. Disconnecting switch G3 is connected to disconnecting switch G1, and disconnecting switch G4 is connected to the input terminal of the inductor group adjustment circuit. In this embodiment 1, the connection and disconnection of the typical fixed series capacitor compensation device are controlled by disconnecting switch G2, and the connection and disconnection of the series capacitor bank C are controlled by disconnecting switches G3 and G4. The zinc oxide MOV1 (non-linear resistor) is used to protect the series capacitor bank C from being burned out.

[0029] like Figure 3 As shown, the inductor group adjustment circuit includes a series-parallel inductor group, a second overvoltage protection device, a variable resistor MOV2, and a disconnecting switch G6. The input terminal of the series-parallel inductor group is connected to the disconnecting switch G4 via the disconnecting switch G5. The output terminal of the series-parallel inductor group is connected to the input terminal of the overcurrent protection circuit via the disconnecting switch G7. The second overvoltage protection device, the zinc oxide MOV2 (non-linear resistor), and the disconnecting switch G6 are connected in parallel with the series-parallel inductor group, and the disconnecting switch G6 is connected in series with the current limiter Q.

[0030] In this embodiment, as Figure 3 As shown, the series-parallel inductor group includes M series inductor elements LM, where M = 1, 2, 3... M, N parallel inductor elements LN', where N = 1, 2, 3... N, N series circuit breakers KN', where N = 1, 2, 3... N, and M parallel circuit breakers KM, where M = 1, 2, 3... M. The M series inductor elements LM are connected in series sequentially, and each series inductor element LM is connected in parallel to a corresponding parallel circuit breaker KM. The N parallel inductor elements LN' are connected in parallel across the series circuit of the M series inductor elements LM, and each parallel inductor element LN' is connected in series to a corresponding series circuit breaker KN', thus forming a series-parallel inductor group.

[0031] In this invention, the specific values ​​of M and N can be determined according to the load connected to the power grid (the values ​​of M and N can be the same or different), and are usually set to 70%-80% of the maximum value of the special load.

[0032] In Example 1, the connection and disconnection of the inductor group adjustment circuit are controlled by isolating switch G6, and the connection and disconnection of the series and parallel inductor groups are controlled by isolating switches G5 and G7. Metal oxide zinc oxide MOV2 (non-linear resistor) is used to protect the series and parallel inductor groups from burning out.

[0033] like Figure 1 As shown, the overcurrent protection circuit includes a circuit breaker K and an overcurrent reactor L connected in parallel. The input terminal of the overcurrent protection circuit is connected to the disconnecting switch G7, and the output terminal is connected to the output terminal B of the distribution cabinet. The connection and disconnection of the overcurrent reactor L are controlled by the circuit breaker K.

[0034] In this embodiment 1, a first voltage protection device and a variable resistor MOV1 are connected in parallel across both ends of the general fixed series capacitor compensation device C and the inductor group adjustment circuit. The first voltage protection device includes a spark gap GAP, a circuit breaker Kc, and a damping device RL. The spark gap GAP and the circuit breaker Kc are connected in parallel and then connected in series with the damping device RL. The voltage protection device is used to release the electrical energy after short-circuiting the series capacitor group C.

[0035] In this embodiment 1, disconnecting switches G1, G2, G3, G4, G5, G6, G7, G8, and G9 are all high-speed eddy current switches. Circuit breakers K and K... M K N Kc and KL are all vacuum arc-extinguishing circuit breakers. The specific model can be selected based on the actual situation and appropriate parameters.

[0036] In this embodiment 1, the disconnecting switch and circuit breaker are controlled to connect and disconnect by a controller installed in the distribution cabinet.

[0037] In this invention, the inductor group adjustment circuit can be equipped with appropriate parameter devices to increase or decrease the value and quantity of series inductors and parallel inductor groups, depending on the actual situation. The specific value of the overcurrent reactor L in the overcurrent protection circuit can also be selected with appropriate parameter devices to ensure that the main components of the circuit are protected from damage in the worst-case short-circuit condition.

[0038] The operation modes of this invention can be divided into three types: conventional series capacitor compensation operation mode; fine-tuning series reverse compensation mode for special occasions; and short-circuit fault operation mode.

[0039] (1) Conventional fixed series capacitor compensation principle:

[0040] Under normal operating conditions, the inherent impedance of the line during power transmission is inductive, increasing the overall impedance value of the line. Capacitive compensation is needed to offset part of the inductive reactance. A typical fixed series capacitor compensation device C includes a series capacitor bank C, which is used to compensate for the inductive reactance in the circuit. The input terminal of the series capacitor bank C is connected to the input terminal A of the distribution cabinet via a disconnecting switch G1. Its output terminal is connected to the output terminal B of the distribution cabinet via an inductor group adjustment circuit and an overcurrent protection circuit. A metal oxide zinc rheostat MOV1 (nonlinear resistor) and a first overvoltage protection device are connected in parallel across the two ends of the series capacitor bank C. A high-speed eddy current switch G2 is connected in parallel across the two ends of the first overvoltage protection device. A discharge protection system is used to release the energy of the series capacitor bank C after short-circuiting protection. In this invention, disconnecting switches G3 and G4 are also added. The input terminal of disconnecting switch G2 is connected to the same terminal as the input terminal of disconnecting switch G3, and the output terminal of disconnecting switch G2 is connected to the output terminal of disconnecting switch G4. It facilitates isolation and equipment replacement during maintenance, and can also be connected to an overcurrent reactor L in case of line faults to limit the intensity of short-circuit current in the circuit, greatly reducing the impact of short-circuit current on electrical equipment.

[0041] Conventional series capacitor compensation operation modes include:

[0042] Under normal operating conditions, capacitive compensation is needed to offset part of the inductive reactance. At this time, the circuit breaker K of the series capacitor bank C... C The circuit breaker Kc is always in the open state, and the switching of the series capacitor bank C is determined by the disconnecting switch G2. When the current of the line is normal, the circuit breaker Kc is in the open state, which puts the series capacitor bank C into operation to compensate for the reactance of the transmission line; at this time, the disconnecting switch G6, which controls the regulating circuit of the inductor group, is in the closed state, so that the regulating circuit of the inductor group is not connected to the line.

[0043] When a short-circuit fault occurs, the general fixed series capacitor compensation device C determines the switching mode of the series capacitor bank C according to different fault types:

[0044] When a single-phase short-circuit fault occurs within the zone, the non-faulty phase of the general fixed series capacitor compensation device C remains operational, and the faulty phase disconnector G2 closes to bypass the series capacitor bank C. After a certain period of time (avoiding the re-connection time of the line circuit breaker), once the system has returned to stability, the faulty phase disconnector G2 opens, restoring operation to the faulty phase. When a two-phase or three-phase short-circuit fault occurs within the zone, the three-phase disconnector G2 of the general fixed series capacitor compensation device C closes, causing the series capacitor bank C to be taken out of operation. After the fault is cleared and a certain period of time (avoiding the re-connection time of the line circuit breaker), the three-phase series capacitor bank C is re-operated.

[0045] When a fault occurs outside the zone, the series capacitor bank C remains in operation and does not operate.

[0046] (2) Series fine-tuning inverse compensation in special cases:

[0047] When a line is operating with a large amount of capacitive load, its inherent impedance during power transmission is inductive. This inductance will partially offset the capacitive load, but situations may arise where the load capacity is too large, resulting in insufficient line capacity compensation. In such cases, inductive compensation is needed to fill the gap. The device includes a series compensation inductor group (composed of M series inductors L1, L2, L3, ...) and a parallel compensation inductor group (composed of N parallel inductors L1', L2', L3', ...). The series compensation inductor group is interconnected via disconnect switches K1, K2, K3, etc., and can display different impedance values ​​to meet real-time line requirements. The input terminal of the series-compensated inductor group is connected to the input terminal of a general fixed series capacitor compensation device C via isolating switch G5. Its output terminal is connected to the input terminal of an overcurrent protection circuit via isolating switch G7. A metal oxide zinc rheostat MOV2 (non-linear resistor) and a voltage protection device are connected in parallel across the two ends of the series-compensated inductor group. An isolating switch G6 is connected in parallel across the two ends of the metal oxide zinc rheostat MOV2 (non-linear resistor) and the second voltage protection device. Isolating switch G6 controls the connection and disconnection of the series-parallel inductor group. The second voltage protection device is used to release the energy of the series-compensated inductor group after short-circuit protection. This invention also adds isolating switches G5 and G7. The input terminal of isolating switch G6 is connected to the input terminal of isolating switch G5, and its output terminal is connected to the output terminal of isolating switch G7. This facilitates isolation and equipment replacement during maintenance. It can also be used to limit the intensity of the short-circuit current in the circuit when a short-circuit fault occurs, greatly reducing the impact of the short-circuit current on electrical equipment.

[0048] Special case series fine-tuning inverse compensation method:

[0049] When a large amount of capacitive load is connected to the line, the overall electrical conductivity of the line may become capacitive. In this case, disconnector G6 is open, and simultaneously disconnectors G5 and G7 at both ends of the series-parallel inductor group are closed. When the current in the line is normal, circuit breaker Kc is in the open state, allowing the series capacitor bank C to operate and compensate for the transmission line capacitance. At this time, the variable capacitor section can be controlled as needed: when the special load is small, disconnector G2 controlling the general fixed series capacitor compensation device C is in the open state, allowing the fixed capacitor section to remain connected to the line. If the special load is large, the general fixed series capacitor compensation device C will act as a load; in this case, the fixed capacitor bank disconnector G2 needs to be closed to prevent the capacitor bank from connecting to the line, reducing the capacitive load pressure.

[0050] When a short-circuit fault occurs, the micro-controllable fixed series compensation device of the present invention determines the switching mode of the series-parallel inductor group according to different fault types:

[0051] When a single-phase short-circuit fault occurs within the zone, the non-faulty phases of the entire micro-controllable fixed series compensation device remain operational. The faulty phase isolating switch G6 closes, bypassing the series-parallel inductor group and allowing the series capacitor bank C to connect to the circuit; alternatively, isolating switches G2 and G6 are closed simultaneously, bypassing both the series-parallel inductor group and the series capacitor bank C. After a certain period (avoiding the re-energization time of the line circuit breaker), once the system returns to stability, the circuit breaker (K) of the series-parallel inductor group is adjusted. M K N To obtain appropriate electrical compensation values, the disconnector switch G6 of the series-parallel inductor group of the faulty phase opens first, followed by the bypass switch G2 of the series capacitor group C of the faulty phase, thereby restoring operation to the faulty phase.

[0052] When a two-phase or three-phase short-circuit fault occurs in the area, the three-phase bypass switch G6 of the series-parallel inductor group closes, causing the series-parallel inductor group L to be taken out of operation. The same applies to the fixed series capacitor group. After the fault is cleared and a certain period of time has elapsed (before the circuit breaker is reset), the three-phase micro-controllable fixed series compensation device is put back into operation.

[0053] When a fault occurs outside the zone, the micro-controllable fixed series compensation device remains operational but does not activate.

[0054] Normal operating mode:

[0055] During normal operation of the line, depending on the load conditions, the disconnecting switches G2 and G6 control the general fixed series capacitor compensation device C and the inductor group adjustment circuit to connect to the line, compensate for the distributed reactance in the line, improve the stability of the power system, improve the voltage quality of the line, and improve the comprehensive utilization rate of electrical energy; the circuit breaker K connected in parallel across the overcurrent reactor L is in the closed state, short-circuiting the overcurrent reactor L in the device, realizing zero loss of the overcurrent reactor L.

[0056] Short-circuit operating status:

[0057] In the event of a line short-circuit fault, the isolating switch G2 of the general fixed series capacitor compensation device C and the isolating switch G6 of the inductor group regulating circuit are closed, isolating the series capacitor group C from the series-parallel inductor group in the line. Simultaneously, the circuit breaker is immediately tripped, connecting the overcurrent reactor L in the series circuit to limit the intensity of the short-circuit current, reducing its impact on electrical equipment in the power system and preventing further expansion of the short-circuit fault. This avoids the contradiction of excessively low voltage at the user end under rated current after meeting the maximum short-circuit current requirement.

[0058] The disconnect switches G1, G8, and G9 on the bus are used for routine maintenance and fault repair and replacement of components without power interruption. By using disconnect switches G1, G8, and G9, maintenance without power interruption can be achieved, which greatly improves the reliability and safety of power supply and avoids economic losses caused by power outage maintenance.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An improved micro-controllable fixed series compensation device with overcurrent protection, characterized in that, The device includes a general fixed series capacitor compensation device C, an inductor group adjustment circuit, and an overcurrent protection circuit. The general fixed series capacitor compensation device C, the inductor group adjustment circuit, and the overcurrent protection circuit are connected in series to form a micro-controllable fixed series compensation device. The two ends of the micro-controllable fixed series compensation device are connected in parallel with a disconnecting switch G8. The input terminal of the general fixed series capacitor compensation device C in the micro-controllable fixed series compensation device is connected to the input terminal A of the distribution cabinet via a disconnecting switch G1. The output terminal of the overcurrent protection circuit in the micro-controllable fixed series compensation device is connected to the output terminal B of the distribution cabinet via a disconnecting switch G9. The inductor group adjustment circuit includes a series-parallel inductor group, a second overvoltage protection device, a variable resistor MOV2, and a disconnecting switch G6. The input terminal of the series-parallel inductor group is connected to the disconnecting switch G4 via the disconnecting switch G5. The output terminal of the series-parallel inductor group is connected to the input terminal of the overcurrent protection circuit via the disconnecting switch G7. The second overvoltage protection device, the variable resistor MOV2, and the disconnecting switch G6 are connected in parallel with the series-parallel inductor group, and the disconnecting switch G6 is connected in series with the current limiter Q. The series-parallel inductor group includes M series inductor elements LM, where M = 1, 2, 3... M, N parallel inductor elements LN', where N = 1, 2, 3... N, N series circuit breakers KN', where N = 1, 2, 3... N, and M parallel circuit breakers KM, where M = 1, 2, 3... M. The M series inductor elements LM are connected in series sequentially, and each series inductor element LM is connected in parallel to a corresponding parallel circuit breaker KM. The N parallel inductor elements LN' are connected in parallel across the series circuit of the M series inductor elements LM, and each parallel inductor element LN' is connected in series to a corresponding series circuit breaker KN', thus forming the series-parallel inductor group.

2. The improved micro-controllable fixed series compensation device with overcurrent protection according to claim 1, characterized in that, The general fixed series capacitor compensation device C includes a series capacitor bank C, a first overvoltage protection device, a variable resistor MOV1, and a disconnect switch G2. The first overvoltage protection device, the variable resistor MOV1, and the disconnect switch G2 are connected in parallel with the series capacitor bank C. The series capacitor bank C includes a disconnect switch G3, a disconnect switch G4, and the series capacitor bank C. The disconnect switches G3 and G4 are connected in series at both ends of the series capacitor bank C. The disconnect switch G3 is connected to the disconnect switch G1, and the disconnect switch G4 is connected to the input terminal of the inductor group adjustment circuit.

3. The improved micro-controllable fixed series compensation device with overcurrent protection according to claim 2, characterized in that, Both the rheostats MOV1 and MOV2 are zinc oxide rheostats.

4. The improved micro-controllable fixed series compensation device with overcurrent protection according to claim 2, characterized in that, The first overvoltage protection device includes a spark gap GAP, a circuit breaker Kc, and a damping device RL, wherein the spark gap GAP and the circuit breaker Kc are connected in parallel and then connected in series with the damping device RL.

5. The improved micro-controllable fixed series compensation device with overcurrent protection according to claim 2, characterized in that, The second overvoltage protection device includes a spark gap GAP and a circuit breaker K. L and damping device RL, wherein the spark gap GAP and circuit breaker K L They are connected in parallel and then connected in series with the damping device RL.

6. The improved micro-controllable fixed series compensation device with overcurrent protection according to claim 2, characterized in that, The overcurrent protection circuit includes a circuit breaker K and an overcurrent reactor L connected in parallel. The input terminal of the overcurrent protection circuit is connected to the disconnecting switch G7, and the output terminal is connected to the output terminal B of the distribution cabinet via the disconnecting switch G9.

7. The improved micro-controllable fixed series compensation device with overcurrent protection according to claim 4, characterized in that, All disconnect switches are high-speed eddy current switches.

8. The improved micro-controllable fixed series compensation device with overcurrent protection according to claim 4, characterized in that, All circuit breakers mentioned are vacuum arc-extinguishing circuit breakers.

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