Control circuit and control method

Abstract

The application discloses a control circuit and a control method, relates to the technical field of extra-high voltage power transmission, and is used for flexibly adjusting the output voltage of an extra / ultra-high voltage power transmission system. The control circuit is applied to the extra / ultra-high voltage power transmission system. The control circuit can output inductive reactive power with different capacities by turning on or turning off a plurality of control valve groups and control switches, so as to achieve the purpose of adjusting the output voltage of the extra / ultra-high voltage power transmission system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of extra-high voltage power transmission, and in particular to a control circuit and a control method. BACKGROUND

[0002] In an extra / ultra-high voltage power transmission system, for example, in a wind power generation system, due to the long distance of the power transmission line, the large power transmission capacity and the instability of the power transmission voltage of the wind power generation, the wind power generation system has a high energy consumption in the power transmission process.

[0003] In order to reduce the energy consumption of the extra / ultra-high voltage power transmission system in the power transmission process, the output voltage of the extra / ultra-high voltage power transmission system is usually adjusted by reactive power compensation, so as to keep the output voltage of the extra / ultra-high voltage power transmission system stable. Therefore, how to adjust the output voltage of the extra / ultra-high voltage power transmission system becomes a problem to be solved. SUMMARY

[0004] The present application provides a control circuit and a control method for flexibly adjusting the output voltage of an extra / ultra-high voltage power transmission system.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, a control circuit is provided, which comprises a first reactor, a second reactor, a third reactor, a first control valve group, a second control valve group, a first control switch and a second control switch.

[0007] The first end of the first reactor is connected to the voltage output end of the extra-high voltage power transmission system, the second end of the first reactor is used for grounding, the third end of the first reactor is connected to the first end of the second reactor and the first end of the first control valve group respectively, the fourth end of the first reactor is connected to the second end of the third reactor; the first control valve group is connected in parallel with the first control switch, the first end of the first control valve group is connected to the first end of the second reactor, and the second end of the first control valve group is connected to the second end of the third reactor; the second control valve group is connected in parallel with the second control switch, the first end of the second control valve group is connected to the first end of the third reactor, and the second end of the second control valve group is connected to the second end of the third reactor.

[0008] Based on the control circuit provided in the first aspect, the control circuit can output reactive power of different capacities by controlling the conduction or cut-off of the first control valve group and the second control valve group, and controlling the disconnection or closure of the first control switch and the second control switch. Since the reactive power of different capacities can be used to adjust the output voltage of the extra / ultra-high voltage power transmission system, the control circuit provided in the present application can flexibly adjust the output voltage of the extra / ultra-high voltage power transmission system.

[0009] In a possible implementation, the control circuit further includes a fourth reactor and a fifth reactor, a first end of the fourth reactor is connected with a second end of the first control switch, and a second end of the fourth reactor is connected with a second end of the first control valve group; a first end of the fifth reactor is connected with a second end of the second control switch, and a second end of the fifth reactor is connected with a second end of the second control valve group.

[0010] In a possible implementation, the first control valve group includes M first power modules connected in series, the second control valve group includes N second power modules connected in series, the first power modules and the second power modules are different, and M and N are positive integers and M is greater than N.

[0011] In a possible implementation, the first power module includes a first CT, a first resistor, a second resistor, a first capacitor, a first thyristor, a second thyristor, a first negative thyristor gate trigger unit, and a first positive thyristor gate trigger unit; a second end of the first CT is connected with an anode of the first thyristor, a first end of the first negative thyristor gate trigger unit, a first end of the second resistor, and a cathode of the second thyristor respectively; a primary winding end of the first CT is connected with the first negative thyristor gate trigger unit, and a secondary winding end of the first CT is connected with the first positive thyristor gate trigger unit; a second end of the first negative thyristor gate trigger unit is connected with the first end of the first resistor, a first end of the first capacitor is connected with a second end of the first resistor, and a second end of the first capacitor is connected with a first end of the first positive thyristor gate trigger unit; the anode of the first thyristor is connected with the first end of the first negative thyristor gate trigger unit, a cathode of the first thyristor is connected with a second end of the first positive thyristor gate trigger unit, and a gate of the first thyristor is connected with a third end of the first positive thyristor gate trigger unit; the anode of the second thyristor is connected with the second end of the first positive thyristor gate trigger unit, the cathode of the second thyristor is connected with the first end of the first negative thyristor gate trigger unit, and a gate of the second thyristor is connected with a third end of the first negative thyristor gate trigger unit; the first end of the second resistor is connected with the first end of the first negative thyristor gate trigger unit, and the second end of the second resistor is connected with the second end of the first positive thyristor gate trigger unit.

[0012] In a possible implementation, the second power module includes a second CT, a third resistor, a fourth resistor, a second capacitor, a third thyristor, a fourth thyristor, a second negative thyristor gate trigger unit, and a second positive thyristor gate trigger unit.

[0013] The second end of the second energy-taking CT is connected with the anode of the third thyristor, the first end of the second negative thyristor gate trigger unit, the first end of the fourth resistor and the cathode of the fourth thyristor; the primary winding end of the second energy-taking CT is connected with the second negative thyristor gate trigger unit, and the secondary winding end of the second energy-taking CT is connected with the second positive thyristor gate trigger unit; the second end of the second negative thyristor gate trigger unit is connected with the first end of the third resistor, the first end of the second capacitor is connected with the second end of the third resistor, and the second end of the second capacitor is connected with the first end of the second positive thyristor gate trigger unit; the anode of the third thyristor is connected with the first end of the second negative thyristor gate trigger unit, the cathode of the third thyristor is connected with the second end of the second positive thyristor gate trigger unit, and the gate of the third thyristor is connected with the third end of the second positive thyristor gate trigger unit; the anode of the fourth thyristor is connected with the second end of the second positive thyristor gate trigger unit, the cathode of the fourth thyristor is connected with the first end of the second negative thyristor gate trigger unit, and the gate of the fourth thyristor is connected with the third end of the second negative thyristor gate trigger unit; the first end of the fourth resistor is connected with the first end of the second negative thyristor gate trigger unit, and the second end of the fourth resistor is connected with the second end of the second positive thyristor gate trigger unit.

[0014] In a possible implementation, the control circuit further includes a controller, the controller is connected with the first control valve group, the second control valve group, the first control switch and the second control switch respectively, and the controller is configured to control the first control valve group and the second control valve group to be turned on or turned off and control the first control switch and the second control switch to be closed or opened according to the input voltage of the UHV power transmission system.

[0015] In a possible implementation, the controller is specifically configured to send a first trigger signal to the second control valve group and send a first closing signal to the second control switch when the input voltage of the UHV power transmission system exceeds a first preset threshold value, and the first trigger signal is used to trigger the second control valve group to be turned on, and the first closing signal is used to instruct the second control switch to be closed.

[0016] In a possible implementation, the controller is specifically configured to send a second trigger signal to the first control valve group and send a second closing signal to the first control switch when the input voltage of the UHV power transmission system exceeds a second preset threshold value, and the second preset threshold value is greater than the first preset threshold value, the second trigger signal is used to trigger the first control valve group to be turned on, and the second closing signal is used to instruct the first control switch to be closed.

[0017] In a second aspect, a control device is provided, and the control device includes the control circuit of the first aspect and any possible implementation of the first aspect.

[0018] The control device provided in the above application is applied to the corresponding control circuit provided in the above, and the beneficial effects achieved thereby can refer to the beneficial effects of the corresponding solutions of the corresponding control circuit provided in the above, which will not be described herein again. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A structural schematic diagram of a control circuit provided for an embodiment of the present application;

[0020] Figure 2 A circuit schematic diagram of another control circuit provided for an embodiment of the present application;

[0021] Figure 3 A schematic diagram of a trigger signal provided for an embodiment of the present application;

[0022] Figure 4 A current curve schematic diagram of a thyristor conduction period provided for an embodiment of the present application;

[0023] Figure 5 A current curve schematic diagram of a third thyristor conduction period provided for an embodiment of the present application;

[0024] Figure 6 A flowchart of a control method provided for an embodiment of the present application;

[0025] Figure 7 A flowchart of another control method provided for an embodiment of the present application. DETAILED DESCRIPTION

[0026] As a solution to the different needs of reactive voltage regulation and overvoltage limitation in the process of EHV / UHV power transmission, controlled shunt reactors (CSRs) have been widely used. CSRs mainly include magnetic valve type and step switching type. Since the step switching type CSR is relatively simple to implement and can better meet the manufacturing technical requirements of high voltage and large capacity, the current UHV high resistance is mainly of the step switching type.

[0027] Among them, the main principle of the step switching type controllable high resistance is to change the equivalent impedance of the low voltage side of the high impedance transformer by using thyristor valves and mechanical on-off control switches to adjust the output capacity of the CSR. In turn, the output voltage of the EHV / UHV system can be adjusted. Therefore, the problem of frequent switching of reactive power compensation equipment caused by the voltage being too high during light load of the EHV / UHV transmission line and the random fluctuation of wind power can be solved.

[0028] Based on this, the control circuit provided in the embodiments of the present application can be applied to the extra / ultra high voltage power transmission system. The control circuit can output reactive power of different capacities through the on or off of the plurality of control valve groups and control switches, so as to regulate the output voltage of the extra / ultra high voltage power transmission system. For example, when the input voltage of the extra / ultra high voltage power transmission system is too high, the control circuit can increase the output reactive power to reduce the output voltage; when the input voltage of the extra / ultra high voltage power transmission system is too low, the control circuit can reduce the output reactive power to increase the output voltage.

[0029] The control circuit provided in the embodiments of the present application can be applied to the above-mentioned CSR. For example, the control circuit can be applied to the CSR, or a chip or a system on chip in the CSR, without limitation. The control circuit can be arranged at the power transmission end in the extra / ultra high voltage power transmission system. For example, the control circuit can be arranged at the bus of the power transmission line in the extra / ultra high voltage power transmission system.

[0030] In an example, as shown in FIG. 1, the control circuit provided in the embodiments of the present application can include a first reactor L0, a second reactor L1, a third reactor L2, a first control valve group, a second control valve group, a first control switch DL1, and a second control switch DL2. Figure 1

[0031] The first end of the first reactor L0 is connected with the power transmission end V in the extra / ultra high voltage power transmission system, the second end is used for grounding (for example, through the reactor LA), and the third end is connected with the first end of the second reactor L1 and the first end of the first control valve group respectively. The fourth end is connected with the second end of the third reactor L2.

[0032] The first control valve group is connected in parallel with the first control switch DL1. The first end of the first control valve group is also connected with the first end of the second reactor L1, and the second end of the first control valve group is connected with the second end of the third reactor L2.

[0033] The second control valve group is connected in parallel with the second control switch DL2. The first end of the second control valve group is also connected with the first end of the third reactor L2, and the second end of the second control valve group is connected with the second end of the third reactor.

[0034] ​It should be noted that the first control switch DL1 and the second control switch DL2 can be mechanical switches. The models of the first and second control valve groups, the first reactor L0, the second reactor L1, and the third reactor L2 can be set as needed. For example, the rated voltage of the first control valve group can be kilovolts (kV) and the rated current can be 3480 amps (A); the rated voltage of the second control valve group can be 34kV and the rated current can be 2299A; the first reactor L0 can be a reactor with a rated current of 3450A, a rated voltage of 63 kV, and a rated inductive reactance of 18.26 ohms (Ω); the second reactor L1 can be a reactor with a rated current of 2166A, a rated voltage of 19.69kV, and a rated inductive reactance of 9.13Ω; and the third reactor L2 can be a reactor with a rated current of 1058A, a rated voltage of 34kV, and a rated inductive reactance of 27.39Ω.

[0035] Furthermore, based on the above examples and Figure 1 Taking a 1000kV rated input voltage and a 600 Mvar rated output capacity of the control circuit as an example in an ultra-high voltage / extra-high voltage transmission system, that is, when the second resistor L1 and the third resistor L2 are in a short-circuit state, the output capacity of the control circuit can be 600 Mvar. Based on the data in the above example, since the rated inductive reactance of the second resistor is 0.5 times that of the first resistor L0, and the rated inductive reactance of the third resistor is 1.5 times that of the first resistor, the output capacity of the control circuit can be 200 Mvar when both the first control switch DL1 and the second control switch DL2 are open; when the second control switch DL2 is closed and the second control switch DL1 is open, the output capacity of the control circuit can be 400 Mvar; and when the first control switch DL1 is closed, the output capacity of the control circuit can be 600 Mvar.

[0036] In one possible implementation, the first control valve assembly may include multiple first power modules ( Figure 1 Only three are shown in the diagram, such as first power modules 1 to 3. For example, there could be 34 first power modules. These multiple first power modules are connected in series.

[0037] For example, such as Figure 2 As shown, a first power module may include a first power extraction CTm, a first resistor R1, a second resistor R2, a first capacitor C1, a first thyristor Tm+, a second thyristor Tm-, a first negative thyristor gate trigger unit TEm-, and a first positive thyristor gate trigger unit TEm+.

[0038] The second end of the first energy-taking CTm is connected with the anode of the first thyristor Tm+, the first end of the first negative thyristor gate trigger unit TEm-, and the first end of the second resistor R2, respectively. The primary winding end CTm-1 of the first energy-taking CTm is connected with the first negative thyristor gate trigger unit TEm-, and the secondary winding end CTm-2 is connected with the first positive thyristor gate trigger unit Tem+. The second end of the first negative thyristor gate trigger unit TEm- is connected with the first end of the first resistor R1. The second end of the first resistor R1 is connected with the first end of the first capacitor C1. The second end of the first capacitor C1 is connected with the first end of the first positive thyristor gate trigger unit TEm+.

[0039] The anode of the first thyristor Tm+ is connected with the first end of the first negative thyristor gate trigger unit TEm-, the cathode is connected with the second end of the first positive thyristor gate trigger unit TEm+, and the gate is connected with the third end of the first positive thyristor gate trigger unit TEm+.

[0040] The anode of the second thyristor Tm- is connected with the second end of the first positive thyristor gate trigger unit TEm+, the cathode is connected with the first end of the first negative thyristor gate trigger unit TEm-, and the gate is connected with the third end of the first negative thyristor gate trigger unit TEm-.

[0041] The first end of the second resistor R2 is connected with the first end of the first negative thyristor gate trigger unit TEm-, and the second end is connected with the second end of the first positive thyristor gate trigger unit TEm+.

[0042] It should be noted that the resistance values of the first resistor R1 and the second resistor R2, the type and size of the first capacitor C1, the first thyristor Tm+, the second thyristor Tm-, the first negative thyristor gate trigger unit TEm-, and the first positive thyristor gate trigger unit TEm+ can be set as needed. For example, the resistance value of the first resistor R1 can be 45Ω, the resistance value of the second resistor R2 can be 300KΩ, the capacitance of the first capacitor C1 can be 1.5 microfarad (μF), the first thyristor Tm+ and the second thyristor Tm- can be 4200A / 6500V high-voltage high-power full-pressure connection thyristors

[0043] In a possible implementation manner, the second control valve group can include a plurality of second power modules (for example, the second power module 1 to the second power module 3). Figure 1 For example, 28 second power modules can be included. The plurality of second power modules are connected in series.

[0044] For example, as shown in FIG. 1, the second control valve group can include a plurality of second power modules (for example, the second power module 1 to the second power module 3). Figure 2As shown, one second power module can include a second power take-off CTn, a third resistor R3, a fourth resistor R4, a second capacitor C2, a third thyristor Tn+, a fourth thyristor Tn-, a second negative thyristor gate trigger unit TEn-, and a second positive thyristor gate trigger unit TEn+.

[0045] The second end of the second power take-off CTn is connected with the anode of the third thyristor Tn+, the first end of the second negative thyristor gate trigger unit TEn-, and the first end of the fourth resistor R4. The primary winding end CTn-1 of the second power take-off CTn is connected with the second negative thyristor gate trigger unit TEn-, and the secondary winding end CTn-2 is connected with the second positive thyristor gate trigger unit TEn+. The second end of the second negative thyristor gate trigger unit TEn- is connected with the first end of the third resistor R3. The second end of the third resistor R3 is connected with the first end of the second capacitor C2. The second end of the second capacitor C2 is connected with the first end of the second positive thyristor gate trigger unit TEn+.

[0046] The anode of the third thyristor Tn+ is connected with the first end of the second negative thyristor gate trigger unit TEn-, the cathode is connected with the second end of the second positive thyristor gate trigger unit TEn+, and the gate is connected with the third end of the second positive thyristor gate trigger unit TEn+.

[0047] The anode of the fourth thyristor Tn- is connected with the second end of the second positive thyristor gate trigger unit TEn+, the cathode is connected with the first end of the second negative thyristor gate trigger unit TEn-, and the gate is connected with the third end of the second negative thyristor gate trigger unit TEn-.

[0048] The first end of the fourth resistor R4 is connected with the first end of the second negative thyristor gate trigger unit TEn-, and the second end is connected with the second end of the second positive thyristor gate trigger unit TEn+.

[0049] It should be noted that the resistance values of the third resistor R3 and the fourth resistor R4, the type of the second capacitor C2, the third thyristor Tn+, the fourth thyristor Tn-, the second negative thyristor gate trigger unit TEn-, and the second positive thyristor gate trigger unit TEn+ can be set as needed. For example, the resistance value of the third resistor R3 can be 90Ω, the resistance value of the fourth resistor R4 can be 300KΩ, the capacitance of the second capacitor C2 can be 1.5μF, and the third thyristor Tn+ and the fourth thyristor Tn- can be 2800A / 6500V high-voltage high-power full-pressure connection thyristors.

[0050] In another possible implementation, in order to ensure normal power taking of the first control valve group and the second control valve group, the first control valve group and the second control valve group can be connected in parallel. Figure 1As shown, the control circuit provided by the embodiment of the present application can further include a fourth reactor L11 and a fifth reactor L22.

[0051] The first end of the fourth reactor L11 is connected with the second end of the first control switch DL1, and the second end of the fourth reactor L11 is connected with the second end of the first control valve group. The first end of the fifth reactor L22 is connected with the second end of the second control switch DL2, and the second end of the fifth reactor L22 is connected with the second end of the second control valve group.

[0052] It should be noted that the models of the fourth reactor L11 and the fifth reactor L22 can be set as needed. For example, the fourth reactor L11 can be a reactor with a rated current of 2700 A, a rated voltage of 5.535 kV, and a rated inductance of 6.525 mH; and the fifth reactor L12 can be a reactor with a rated current of 1961 A, a rated voltage of 5.00 kV, and a rated inductance of 8.117 mH.

[0053] Based on the possible implementation, when the first control switch DL1 and the second control switch DL2 are closed, if there is no fourth reactor L11 and fifth reactor L22, there is no voltage across the first control valve group and the second control valve group, and the loop current is 0, and the gate trigger units TEm+, TEn+, TEm+, and TEn+ inside the valve groups all lose power and stop working. Since the fourth reactor L11 and the fifth reactor L22 are directly connected in series with the first control switch DL1 and the second control switch DL2, respectively, after the first control switch DL1 and the second control switch DL2 are closed, the working current flows through the fourth reactor L11 and the fifth reactor L22, so that a certain amplitude of voltage (about 5 kV) is generated across the fourth reactor L11 and the fifth reactor L22, respectively. The voltage is applied across the first control valve group and the second control valve group at the same time, and provides power for the gate trigger units TEm+, TEn+, TEm+, and TEn+ inside the valve groups, thereby monitoring the state of the thyristors and preparing for triggering.

[0054] In another possible implementation, the control circuit provided by the embodiment of the present application can further include a controller (not shown in the figure). The controller can be connected with the first control valve group, the second control valve group, the first control switch DL1, and the second control switch DL2.

[0055] The controller can be configured to control the cutoff or conduction of the first control valve group and the second control valve group, and control the closing or opening of the first control switch DL1 and the second control switch DL2, according to the input voltage of the output end of the extra / ultra high voltage power transmission system.

[0056] An example, when the output voltage of the output end of the extra / ultra-high voltage power transmission system exceeds the first preset voltage, the controller can send a first closing instruction to the second control switch DL2, and send a first trigger signal to the second control valve group.

[0057] The first preset voltage can be set as needed, for example, it can be 1.05 times the rated voltage. For example, it can be 1.05*1000kV=1050kV. The first closing instruction can be used to instruct the second control switch DL2 to close. The first trigger signal can be used to instruct the second control valve group to conduct.

[0058] For example, as shown in Figure 3 , the first trigger signal can be sinωt, and the duration of the first trigger signal can be a preset duration. Wherein, ω, t can be set as needed. The preset duration can be greater than the reliable closing duration of the second control switch. The reliable closing duration of the second control switch can be the duration between the starting time when the second control switch starts to execute the closing action after receiving the first closing instruction and the time when it is completely closed and stable. For example, the reliable closing duration of the second control switch can be 100 milliseconds (ms), and the preset duration can be 500ms.

[0059] The amplitude of the first trigger signal can be set as needed, for example, it can be 43.84√2V, without limitation. In combination with Figure 3 , when the phase of the sine wave is 90°, the first thyristor Tm+ can be triggered to conduct, and when the phase of the sine wave is 270°, the first thyristor Tm+ is cut off and the second thyristor Tm- is turned on. In this way, the first thyristor Tm+ and the second thyristor Tm- can be turned on alternately.

[0060] For example, as shown in a of Figure 4 , when the first control valve group is turned on, the current waveform of the first thyristor Tm+ is shown. As shown in b of Figure 4 , when the second control valve group is turned on, the current waveform of the third thyristor Tn+ is shown.

[0061] Further, since the conduction time of the first thyristor and the second thyristor is much lower than the reliable closing duration of the mechanical switch, when the first control valve group and the first control switch simultaneously receive the closing instruction of the controller, the first control valve group first conducts current, and the first control switch is reliably closed within 100ms. Due to the presence of the fourth reactor L22, the impedance of the energy taking circuit where the first control switch is located is large, so the circuit passes through the first control valve group. After 500ms, since the controller stops sending the first trigger signal to the first control valve group, the first control valve group thyristor is cut off and the current is zero. At this time, the circuit current passes through the first control switch.

[0062] As can be seen from the above, since the thyristor has a short conduction time, only 500 ms per working time, the temperature of the thyristor has not yet risen to the highest temperature. Therefore, the control circuit provided in the embodiments of the present application can meet the cooling requirements of the thyristor valve through natural cooling, thereby simplifying the structure of the control valve group.

[0063] For example, taking the length of the trigger signal as 500 ms as an example, as shown in Figure 5 , it is a schematic diagram of the temperature change curve of the first thyristor and the third thyristor in the conduction period obtained by experimental measurement.

[0064] In another example, when the input voltage of the output end of the EHV / UHV power transmission system exceeds the second preset voltage, the controller can send a second closing instruction to the first control switch and a second trigger signal to the first control valve group.

[0065] The second preset voltage is greater than the first preset voltage. For example, the second preset voltage can be 1.1 times the rated voltage. For example, it can be 1.1*1000kV=1100kV. The second closing instruction can be used to instruct the first control switch DL1 to close. The second trigger signal can be used to instruct the first control valve group to conduct. The amplitude of the second trigger signal is different from that of the first trigger signal. The amplitude of the second trigger signal can be 34kV. The second trigger information can refer to the description of the first trigger signal and will not be repeated here.

[0066] It should be noted that when the detection circuit is initially connected to the EHV / UHV power transmission system, the first control switch and the second control switch of the control circuit are in an open state. That is, the capacity of the detection circuit output is 200Mvar.

[0067] Based on the control circuit provided in the embodiments of the present application, by controlling the conduction and cutoff of the first control valve group and the second control valve group, and controlling the closing or opening of the first control switch and the second control switch, the size of the output capacity can be flexibly controlled according to the output voltage of the EHV / UHV system, so that the output voltage can be adjusted to ensure the stability of the output voltage as much as possible.

[0068] The control method provided in the embodiments of the present application will be described below in combination with the control circuit 100 shown in Figure 1 .

[0069] As shown in Figure 6 , the embodiments of the present application provide a control method applied to the control circuit 100 shown in Figure 1 , the control method comprises the following steps.

[0070] In step 601, the controller obtains the input voltage of the EHV / UHV system.

[0071] Step 602: The controller controls the first control valve group and the second control valve group to be turned on or off according to the input voltage, and controls the first control switch and the second control switch to be closed or opened.

[0072] In one possible implementation, when the input voltage is greater than the first preset voltage, the controller sends a first trigger signal to the second control valve group and a first closing signal to the second control switch.

[0073] The first trigger signal and the first closing signal can be referred to the above description and will not be repeated here.

[0074] In another possible implementation, when the input voltage is greater than the second preset voltage, the controller sends a second trigger signal to the first control valve group and a second closing signal to the second control switch.

[0075] The second trigger signal and the second closing signal can be referred to the above description and will not be repeated here.

[0076] based on Figure 6 The technical solution allows the controller to adjust the reactive power output of the control circuit according to the input voltage of the ultra-high voltage / extra-high voltage system, thereby flexibly adjusting the output voltage of the ultra-high voltage / extra-high voltage system.

[0077] In one possible implementation, such as Figure 7 As shown in the embodiments of this application, the method may further include:

[0078] Step 701: When the control circuit is initially connected to the UHV transmission system, the controller controls the first control switch and the second control switch to be in the open state.

[0079] Based on this embodiment, it is possible to avoid damage to the components of the control circuit due to excessive voltage when the control circuit is connected to an ultra-high voltage / extra-high voltage system.

[0080] The actions, terms, etc., involved in the various embodiments of this application can be referenced interchangeably without limitation. The message names or parameter names in the messages exchanged between the various devices in the embodiments of this application are just examples, and other names may be used in specific implementations without limitation.

[0081] For the convenience of clearly describing the technical solutions of the embodiments of the present application, in the embodiments of the present application, the terms of "first", "second", etc. are used to distinguish the same or similar items with basically the same function and role. For example, the first preset amplitude and the second preset amplitude are only used to distinguish different preset amplitudes, and the order is not limited. Those skilled in the art can understand that the terms of "first", "second", etc. do not limit the quantity and execution order, and the terms of "first", "second", etc. also do not mean that they are necessarily different.

[0082] It should be noted that in the present application, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design scheme described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or having more advantages than other embodiments or design schemes. Rather, the use of the words "exemplary" or "for example" is intended to present the relevant concept in a specific manner.

[0083] In the present application, "at least one" means one or more, and "multiple" means two or more. The association relationship between the associated objects is described, which means that there can be three relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or similar expressions means any combination of these items, including any combination of single item or multiple items. For example, at least one of a, b, or c can represent a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0084] Among them, the actions, terms, etc. involved between the embodiments of the present application can be mutually referenced and not limited. The message name or parameter name in the message between the devices in the embodiments of the present application is only an example, and other names can also be used in specific implementation, which is not limited. The actions involved in the embodiments of the present application are only an example, and other names can also be used in specific implementation.

[0085] The various schemes in the above embodiments of the present application can be combined without contradiction.

[0086] It should be noted that the terms "first", "second" and "third" and the like in the description, claims and drawings of the application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and are not intended to limit the scope of the application to a given embodiment or implementation. Furthermore, the terms "comprise", "include", "contain" and / or "have" should be understood as referring to the possibility that the object in question comprises, includes, contains or has, but does not exclude the presence of one or more additional objects. For example, a process, method, object or apparatus that comprises or includes one step or unit, but not limited to the listed steps or units, can optionally also include one or more additional steps or units that are not listed.

[0087] Those skilled in the art can clearly understand the above-mentioned embodiments of the application through the description of the above embodiments. For the convenience and brevity of description, only the above-mentioned division of functional modules is taken as an example. In actual application, the above-mentioned functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0088] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative, for example, the division of the modules or units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed each other can be through some interface, indirect coupling or communication connection between the devices or units, which can be electrical, mechanical or other forms.

[0089] The units described as separate components can or can not be physically separate, and the components shown as units can be one physical unit or multiple physical units, that is, can be located in one place, or can be distributed to multiple different places. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0090] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. For example, the above-mentioned integrated unit can be realized in the form of hardware.

[0091] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A control circuit, characterized by The control circuit comprises a first reactor, a second reactor, a third reactor, a first control valve group, a second control valve group, a first control switch and a second control switch, and a controller; the controller is connected with the first control valve group, the second control valve group, the first control switch and the second control switch; The first end of the first reactor is connected with a voltage output end of an extra-high voltage power transmission system, the second end of the first reactor is used for grounding, the third end of the first reactor is connected with the first end of the second reactor and the first end of the first control valve group respectively, and the fourth end of the first reactor is connected with the second end of the third reactor. The first control valve group is connected with the first control switch in parallel, the first end of the first control valve group is connected with the first end of the second reactor, and the second end of the first control valve group is connected with the second end of the third reactor; when the input voltage of the voltage output end of the extra-high voltage power transmission system exceeds a first preset voltage, the second control valve group is used for entering a conduction state in response to a first trigger signal of the controller, and the second control switch is used for entering a closed state in response to a first closing instruction of the controller; when the input voltage of the voltage output end of the extra-high voltage power transmission system exceeds a second preset voltage, the first control valve group is used for entering a conduction state in response to a second trigger signal of the controller, and the first control switch is used for entering a closed state in response to a second closing instruction of the controller; the second preset voltage is greater than the first preset voltage; when the first control valve group is in the conduction state and the first control switch is in the closed state, the first output capacity of the control circuit is less than the second output capacity of the control circuit, and the second output capacity is the output capacity of the control circuit when the second control valve group and the first control valve group are in the conduction state and the second control switch and the first control switch are in the closed state. The second control valve group is connected with the second control switch in parallel, the first end of the second control valve group is connected with the first end of the third reactor, and the second end of the second control valve group is connected with the second end of the third reactor.

2. The control circuit of claim 1, wherein, The control circuit further comprises a fourth reactor and a fifth reactor; The first end of the fourth reactor is connected with the second end of the first control switch, and the second end of the fourth reactor is connected with the second end of the first control valve group. The first end of the fifth reactor is connected with the second end of the second control switch, and the second end of the fifth reactor is connected with the second end of the second control valve group.

3. The control circuit according to claim 1 or 2, characterized in that, The first control valve group comprises M first power modules connected in series, the second control valve group comprises N second power modules connected in series, the first power modules and the second power modules are different, M and N are positive integers and M is greater than N.

4. The control circuit of claim 3, wherein, The first power module comprises a first power-on CT, a first resistor, a second resistor, a first capacitor, a first thyristor, a second thyristor, a first negative thyristor gate trigger unit and a first positive thyristor gate trigger unit. The second end of the first power taking CT is connected with the anode of the first thyristor, the first end of the first negative thyristor gate trigger unit, the first end of the second resistor and the cathode of the second thyristor, respectively; the primary winding end of the first power taking CT is connected with the first negative thyristor gate trigger unit, and the secondary winding end of the first power taking CT is connected with the first positive thyristor gate trigger unit; The second end of the first negative thyristor gate trigger unit is connected with the first end of the first resistor, the first end of the second resistor is connected with the first end of the first capacitor, and the second end of the first capacitor is connected with the first end of the first positive thyristor gate trigger unit; The anode of the first thyristor is connected with the first end of the first negative thyristor gate trigger unit, the cathode of the first thyristor is connected with the second end of the first positive thyristor gate trigger unit, and the gate of the first thyristor is connected with the third end of the first positive thyristor gate trigger unit; The anode of the second thyristor is connected with the second end of the first positive thyristor gate trigger unit, the cathode of the second thyristor is connected with the first end of the first negative thyristor gate trigger unit, and the gate of the second thyristor is connected with the third end of the first negative thyristor gate trigger unit; The first end of the second resistor is connected with the first end of the first negative thyristor gate trigger unit, and the second end of the second resistor is connected with the second end of the first positive thyristor gate trigger unit.

5. The control circuit of claim 3, wherein, The second power module comprises a second power taking CT, a third resistor, a fourth resistor, a second capacitor, a third thyristor, a fourth thyristor, a second negative thyristor gate trigger unit and a second positive thyristor gate trigger unit; The second end of the second power taking CT is connected with the anode of the third thyristor, the first end of the second negative thyristor gate trigger unit, the first end of the fourth resistor and the cathode of the fourth thyristor, respectively; the primary winding end of the second power taking CT is connected with the second negative thyristor gate trigger unit, and the secondary winding end of the second power taking CT is connected with the second positive thyristor gate trigger unit; The second end of the second negative thyristor gate trigger unit is connected with the first end of the third resistor, the second end of the third resistor is connected with the first end of the second capacitor, and the second end of the second capacitor is connected with the first end of the second positive thyristor gate trigger unit; The anode of the third thyristor is connected with the first end of the second negative thyristor gate trigger unit, the cathode of the third thyristor is connected with the second end of the second positive thyristor gate trigger unit, and the gate of the third thyristor is connected with the third end of the second positive thyristor gate trigger unit; The anode of the fourth thyristor is connected with the second end of the second positive thyristor gate trigger unit, the cathode of the fourth thyristor is connected with the first end of the second negative thyristor gate trigger unit, and the gate of the fourth thyristor is connected with the third end of the second negative thyristor gate trigger unit; A first end of the fourth resistor is connected to a first end of the second negative thyristor gate trigger unit, and a second end of the fourth resistor is connected to a second end of the second positive thyristor gate trigger unit.

6. A control method characterized by, The method is applied to the control circuit of any one of claims 1-5, and the method comprises: obtaining an input voltage of the UHV power transmission system; controlling the first control valve group and the second control valve group to be turned on or turned off and controlling the first control switch and the second control switch to be closed or opened according to the input voltage of the UHV power transmission system.

7. The control method according to claim 6, characterized by The controlling the first control valve group and the second control valve group to be turned on or turned off and the controlling the first control switch and the second control switch to be closed or opened according to the input voltage of the UHV power transmission system comprises: when the input voltage of the UHV power transmission system exceeds a first preset threshold, sending a first trigger signal to the second control valve group and sending a first closing signal to the second control switch; wherein the first trigger signal is used to trigger the second control valve group to be turned on, and the first closing signal is used to indicate that the second control switch is closed.

8. The control method according to claim 7, characterized by, The controlling the first control valve group and the second control valve group to be turned on or turned off and the controlling the first control switch and the second control switch to be closed or opened according to the input voltage of the UHV power transmission system comprises: when the input voltage of the UHV power transmission system exceeds a second preset threshold, sending a second trigger signal to the first control valve group and sending a second closing signal to the first control switch; wherein the second preset threshold is greater than the first preset threshold, the second trigger signal is used to trigger the first control valve group to be turned on, and the second closing signal is used to indicate that the first control switch is closed.

9. The method according to any one of claims 6-8, characterized in that, The method further comprises: when the control circuit is initially connected to the UHV power transmission system, controlling the first control switch and the second control switch to be in an open state.

10. A computer-readable storage medium having stored thereon instructions, the instructions comprising, When the instructions in the computer readable storage medium are executed by the processor of the computing device, the computing device is enabled to perform the control method of any one of claims 6-9.

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