Resonance elimination device and method for transformer substation

Abstract

The invention discloses a resonance elimination device and method for a transformer substation. The device comprises a main control module, an intelligent switching resonance elimination module and a characteristic quantity sampling module, the input end of the first thyristor is electrically connected with the first end of an open triangle of the voltage transformer cabinet, the output end of the first thyristor is electrically connected with the first end of the contact unit, and the second end of the contact unit is electrically connected with the first end of the nonlinear damping resistor unit. The second end of the nonlinear damping resistor unit is electrically connected with the input end of the second thyristor unit, and the output end of the second thyristor unit is electrically connected with the second end of the open triangle; the open triangle voltage acquisition unit is connected with the open triangle in parallel, and the zero-sequence current acquisition unit is electrically connected with a neutral point of the open triangle; the control end of the first thyristor, the control end of the second thyristor, the control end of the contact unit, the open delta voltage acquisition unit and the zero sequence current acquisition unit are all electrically connected with the main control module. And the method is suitable for multi-scene work.

Description

Technical Field

[0001] The present invention relates to the technical field of substation detuning, and in particular to a detuning device and method for a substation. Background Art

[0002] Ferromagnetic resonance in the power system will generate corresponding ferromagnetic resonance overvoltage, which poses a serious threat to the safe and stable operation of the power grid system. At present, the purpose of suppressing ferromagnetic resonance overvoltage in the power system is generally achieved by combining primary detuning with secondary detuning. However, at present, secondary detuning mostly relies on the open triangle voltage amplitude to judge the fault type, and it is difficult to accurately diagnose the fundamental frequency resonance. Furthermore, the existing detuning device does not control the heat generated by the damping resistor, resulting in accidents such as the burning of the detuning circuit, and the detuning effect of the existing device is not good. At the same time, there is a scenario in the operation and maintenance of the power grid where the open triangle winding is phase-untied. In this process, the function of the microcomputer detuning device fails. If ferromagnetic resonance occurs in the power system at this time, a large ferromagnetic resonance overvoltage will be generated, causing the potential transformer (PT) cabinet to explode, burn, or the PT cabinet high-voltage fuse to melt and other vicious accidents.

[0003] In summary, the current secondary detuning device has inaccurate detuning diagnosis, and the multi-scenario operation causes the power grid to lose the online open-delta detuning function, thereby generating ferromagnetic resonance overvoltage and causing huge harm, which needs to be solved urgently. Summary of the invention

[0004] The present invention provides a harmonic elimination device and method for a substation, which has accurate harmonic elimination diagnosis and is applicable to multiple working scenarios.

[0005] In a first aspect, an embodiment of the present invention provides a harmonic elimination device for a substation, comprising: a main control module, an intelligent switching harmonic elimination module, and a characteristic quantity sampling module;

[0006] The intelligent switching and harmonic elimination module and the characteristic quantity sampling module are both electrically connected to the main control module;

[0007] The intelligent switching harmonic elimination module includes: a nonlinear damping resistor unit, a contact unit and a thyristor unit; the thyristor unit includes a first thyristor and a second thyristor; the input end of the first thyristor is electrically connected to the first end of the open triangle of the voltage transformer cabinet, the output end of the first thyristor is electrically connected to the first end of the contact unit, the second end of the contact unit is electrically connected to the first end of the nonlinear damping resistor unit, the second end of the nonlinear damping resistor unit is electrically connected to the input end of the second thyristor unit, and the output end of the second thyristor is electrically connected to the second end of the open triangle;

[0008] The characteristic quantity sampling module comprises an open triangle voltage acquisition unit and a zero-sequence current acquisition unit, the open triangle voltage acquisition unit is connected in parallel with the open triangle, and the zero-sequence current acquisition unit is electrically connected to the neutral point of the open triangle;

[0009] The control end of the first thyristor, the control end of the second thyristor, the control end of the contact unit, the open triangle voltage acquisition unit and the zero-sequence current acquisition unit are all electrically connected to the main control module.

[0010] In a second aspect, an embodiment of the present invention further provides a method for eliminating harmonics in a substation, which is implemented by using the detuning device for a substation as described in any embodiment of the first aspect. The detuning method for a substation includes:

[0011] Acquire characteristic quantities collected by a characteristic quantity sampling module, wherein the characteristic quantities include an open delta voltage of a voltage transformer cabinet and a zero-sequence current of the voltage transformer cabinet;

[0012] When it is detected that the open triangle voltage is greater than or equal to a first voltage threshold, and the zero-sequence current is greater than or equal to a first current threshold, it is determined that resonance occurs in the substation, and the thyristor unit is controlled to be turned on;

[0013] Obtaining the frequency of the open triangle voltage;

[0014] The resonance type of the substation is determined according to the frequency of the open triangle voltage, and the corresponding contacts in the contact unit are controlled to be turned on according to the resonance type, and the corresponding nonlinear damping resistor in the nonlinear damping resistor unit is used to achieve detuning of the substation.

[0015] The embodiment of the present invention provides a harmonic elimination device and method for a substation, wherein a characteristic quantity sampling module includes an open triangle voltage acquisition unit and a zero-sequence current acquisition unit, and a main control module obtains the analog quantity collected by the characteristic quantity sampling module, can well diagnose the resonance type, and controls and connects the intelligent switching harmonic elimination module at the open triangle of the voltage transformer cabinet to realize the corresponding harmonic elimination function, making up for the gap when the online harmonic elimination temporarily exits the system, and can operate safely and accurately. The harmonic elimination device of the present invention has the advantages of portability, accurate diagnosis, safety and controllability, and is suitable for working in multiple scenarios.

[0016] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of the structure of a harmonic elimination device for a substation provided by an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the structure of an intelligent switching harmonic elimination module provided in an embodiment of the present invention;

[0020] Figure 3 A schematic diagram of the structure of another harmonic elimination device for a substation provided by an embodiment of the present invention;

[0021] Figure 4 A schematic diagram of the external structure of a harmonic elimination device for a substation provided by an embodiment of the present invention;

[0022] Figure 5 A flow chart of a method for eliminating harmonics in a substation provided by an embodiment of the present invention;

[0023] Figure 6 A flow chart of another method for eliminating harmonics in a substation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] Figure 1 A schematic diagram of the structure of a harmonic elimination device for a substation provided by an embodiment of the present invention, Figure 2 This is a schematic diagram of the structure of an intelligent switching harmonic elimination module 120 provided in an embodiment of the present invention. Figure 1 and Figure 2 The harmonic elimination device 100 of the substation includes: a main control module 110, an intelligent switching harmonic elimination module 120 and a characteristic quantity sampling module 130. The intelligent switching harmonic elimination module 120 and the characteristic quantity sampling module 130 are both electrically connected to the main control module 110. The intelligent switching harmonic elimination module 120 includes: a nonlinear damping resistor unit 121, a contact unit 122 and a thyristor unit 123; the thyristor unit 123 includes a first thyristor 1211 and a second thyristor 1212; the input end of the first thyristor 1211 is electrically connected to the first end of the open triangle of the voltage transformer cabinet A, the output end of the first thyristor 1211 is electrically connected to the first end of the contact unit 122, the second end of the contact unit 122 is electrically connected to the first end of the nonlinear damping resistor unit 121, the second end of the nonlinear damping resistor unit 121 is electrically connected to the input end of the second thyristor 1212 unit 123, and the output end of the second thyristor 1212 is electrically connected to the second end of the open triangle. The characteristic quantity sampling module 130 includes an open triangle voltage acquisition unit 131 and a zero-sequence current acquisition unit 132. The open triangle voltage acquisition unit 131 is connected in parallel with the open triangle, and the zero-sequence current acquisition unit 132 is electrically connected to the neutral point of the open triangle; the control end of the first thyristor 1211, the control end of the second thyristor 1212, the control end of the contact unit 122, the open triangle voltage acquisition unit 131 and the zero-sequence current acquisition unit 132 are all electrically connected to the main control module 110.

[0027] Among them, the main control module 110 uses a high-performance computing power microprocessor to execute the compiled detuning algorithm to determine the resonance type of the substation, and drives the intelligent switching detuning module 120 to quickly eliminate the system resonance, and interacts with other module functions to realize functions such as accident recording and recall. The functional interaction includes: providing master clock control for each module of the detuning device 100; obtaining the analog quantity of the characteristic quantity sampling module 130 in real time for multi-channel A / D conversion control; sending commands to the intelligent switching detuning module 120 to control the switching of the detuning function. When the detuning device 100 of the substation is operating normally, the intelligent switching detuning module 120 is connected to the open triangle of the voltage transformer cabinet A through the test line, and the thyristor unit 123 of the intelligent switching detuning module 120 is controlled by the main control module 110, and the corresponding contacts in the contact unit 122 are turned on, which can form a detuning circuit, and the corresponding nonlinear damping resistor in the nonlinear damping resistor unit 121 consumes the ferromagnetic resonance energy to achieve detuning of the substation.

[0028] The characteristic quantity sampling module 130 of the substation detuning device provided in the embodiment of the present invention includes an open triangle voltage acquisition unit 131 and a zero-sequence current acquisition unit 132. The main control module 110 obtains the analog quantity collected by the characteristic quantity sampling module 130, can well diagnose the resonance type, and controls and connects the intelligent switching detuning module 120 at the open triangle of the voltage transformer cabinet A to realize the corresponding detuning function, making up for the gap when the online detuning temporarily exits the system, and can operate safely and accurately. The detuning device 100 of the present invention has the advantages of portability, accurate diagnosis, safety and controllability, and is suitable for multi-scenario work.

[0029] Optionally, based on the above embodiment, continue to refer to Figure 2 The contact unit 122 includes: a first contact S1, a second contact S2, and a third contact S3. The first end of the first contact S1, the first end of the second contact S2, and the first end of the third contact S3 are all electrically connected to the output end of the first thyristor 1211, and the second end of the first contact S1, the second end of the second contact S2, and the second end of the third contact S3 are all electrically connected to the first end of the nonlinear damping resistor unit 121; the control end of the first contact S1, the control end of the second contact S2, and the control end of the third contact S3 are all electrically connected to the main control module 110.

[0030] It should be noted that when the substation does not resonate, the first contact S1, the second contact S2 and the third contact S3 are all disconnected. When the main control module 110 determines that the substation resonates, it controls the corresponding contact to close according to the resonance type, and connects different nonlinear damping resistors in the nonlinear damping resistor unit 121 to achieve detuning. When the substation resonates at the fundamental frequency, the main control module 110 controls the first contact S1 to close, when the substation resonates at the frequency division frequency, the main control module 110 controls the second contact S2 to close, and when the substation resonates at the high frequency, the main control module 110 controls the third contact S3 to close.

[0031] Optionally, based on the above embodiment, continue to refer to Figure 2The nonlinear damping resistor unit 121 includes: a first thermistor R1, a second thermistor R2 and a third thermistor R3; a first end of the first thermistor R1 is electrically connected to a second end of the first contact S1 unit 122, a first end of the second thermistor R2 is electrically connected to a second end of the second contact S2 unit 122, and a first end of the third thermistor R3 is electrically connected to a second end of the third contact S3 unit 122; a second end of the first thermistor R1, a second end of the second thermistor R2 and a second end of the third thermistor R3 are all electrically connected to an input end of the second thyristor 1212; the resistance values ​​of the first thermistor R1, the second thermistor R2 and the third thermistor R3 all change nonlinearly with temperature; the resistance value of the first thermistor R1 is within a first resistance range, and when the main control module 110 detects an opening When the frequency of the triangle voltage is greater than or equal to the first frequency threshold and less than or equal to the second frequency threshold, it is determined that the substation has a fundamental frequency resonance, and the first contact S1 is controlled to be turned on, and the first thermistor R1 is used to achieve detuning of the substation; the resistance of the second thermistor R2 is within the second resistance range, and when the main control module 110 detects that the frequency of the open triangle voltage is less than or equal to the first frequency threshold, it is determined that the substation has a frequency division resonance, and the second contact S2 is controlled to be turned on, and the second thermistor R2 is used to achieve detuning of the substation; the resistance of the third thermistor R3 is within the third resistance range, and when the main control module 110 detects that the frequency of the open triangle voltage is greater than or equal to the second frequency threshold, it is determined that the substation has a high-frequency resonance, and the third contact S3 is controlled to be turned on, and the third thermistor R3 is used to achieve detuning of the substation.

[0032] Among them, the resistance ranges of the first thermistor R1, the second thermistor R2, and the third thermistor R3 are selected by the user according to the requirements of different resonance types for resistance. The resistance of the first thermistor R1 is within the first resistance range, which can meet the resistance requirement of detuning when the substation has a fundamental frequency resonance. The resistance of the second thermistor R2 is within the second resistance range, which can meet the resistance requirement of detuning when the substation has a frequency division resonance. The resistance of the third thermistor R3 is within the third resistance range, which can meet the resistance requirement of detuning when the substation has a high-frequency resonance. Exemplarily, the resistance of the first thermistor R1 includes 5Ω, the resistance of the second thermistor R2 includes 2Ω, and the resistance of the third thermistor R3 includes 20Ω.

[0033] It can be understood that the main control module 110 detects the frequency of the open triangle voltage collected from the open triangle voltage collection unit 131, and determines the resonance type of the substation according to the frequency of the open triangle voltage. The resistance values ​​of the first thermistor R1, the second thermistor R2, and the third thermistor R3 vary nonlinearly with temperature in different resistance ranges, which can well cope with the response time requirements and resistance heat safety requirements under different types of resonance, and ensure the rapidity and safety of the detuning device 100.

[0034] Optionally, based on the above embodiments, the open triangle voltage acquisition unit 131 includes a voltage transformer, and the zero-sequence current acquisition unit 132 includes a current probe (the voltage transformer and the current probe are not shown in the figure); the detection end of the voltage transformer is connected in parallel with the open triangle, and the signal transmission end of the voltage transformer is electrically connected to the main control module 110; the detection end of the current probe is electrically connected to the neutral point of the open triangle, and the signal transmission end of the current probe is electrically connected to the main control module 110.

[0035] The current probe may include a wireless portable current probe. In the embodiment of the present invention, the current probe is used to detect the zero-sequence current of the voltage transformer cabinet A, and the open delta voltage of the voltage transformer cabinet A is collected by the voltage transformer.

[0036] Optionally, based on the above embodiment, the characteristic quantity sampling module 130 further includes: a current transformer and a temperature sensor (the current transformer and the temperature sensor are not shown in the figure); the current transformer and the temperature sensor are both electrically connected to the intelligent switching and harmonic elimination module 120.

[0037] It is understandable that in the embodiment of the present invention, the current transformer is electrically connected to the intelligent switching harmonic elimination module 120 to detect the loop current of the intelligent switching harmonic elimination module 120. The temperature sensor is electrically connected to the intelligent switching harmonic elimination module 120 to detect the loop temperature of the intelligent switching harmonic elimination module 120.

[0038] Figure 3 A schematic diagram of the structure of another harmonic elimination device for a substation provided by an embodiment of the present invention, Figure 4 The external structure diagram of a harmonic elimination device of a substation provided by an embodiment of the present invention is optional, based on the above embodiment, referring to Figure 3 and Figure 4 The harmonic elimination device 100 of the substation also includes: a lithium battery charging and power supply module 140, a communication interface module 150, a storage module 160 and a human-computer interaction module 170; the main control module 110, the characteristic quantity sampling module 130 and the human-computer interaction module 170 are all electrically connected to the lithium battery charging and power supply module 140; the communication interface module 150, the storage module 160 and the human-computer interaction module 170 are all electrically connected to the main control module 110; the human-computer interaction module 170 includes a liquid crystal display screen 171, an operation button 172, a panel printer 173 and a signal light group 174.

[0039] Among them, the lithium battery charging and power supply module 140 includes a high-performance large-capacity lithium battery (not shown in the figure) and a fast charging interface 141, which outputs a specific voltage to meet the device's battery life and is convenient to carry for short-term rotation in multiple substations. Exemplarily, the lithium battery charging and power supply module 140 can use a 4000mAh rechargeable lithium battery to output 5V, 12V, and 24V voltages to power other modules. A 220V fast charging interface can provide 55W fast charging that can be fully charged in one hour, and can be operated for a short time in the substation for 72 hours at a time. The storage module 160 can use a large-capacity solid-state storage medium that can quickly write the state changes of the real-time recording device and store 999 event records and corresponding waveforms. Exemplarily, the storage module 160 can use a 32GB high-speed solid-state SSD, which can store the event displacement records, instruction execution, and voltage waveforms in chronological order. The communication interface module 150 includes various forms of data communication interfaces 151 such as RS485 and RJ-45, which facilitate the device to establish communication with the host computer or the background, report alarm signals to the remote dispatcher, and execute remote commands. The embodiment of the present invention provides an RS485 and an RJ-45 interface to facilitate communication with other devices. The human-computer interaction module 170 includes a liquid crystal display 171, operation buttons 172, a panel printer 173, and a signal light group 174. On the one hand, the liquid crystal display 171 and the signal light group 174 display the device status in real time for the operator to view and obtain, and use the panel printer 173 to print out the corresponding accident records and waveforms; on the other hand, the operator uses the operation button 172 to issue instructions to the device such as "restart", "reset", "confirm" and "return". For example, refer to Figure 4 The liquid crystal display screen 171 can be a 5-inch LCD screen, the operation button 172 includes eight touch-type function buttons and a rocker switch for controlling the power supply of the device, and the signal light group 174 includes 4 signal indicator lights to display the device status: "running", "underpower", "resonance", and "overvoltage". The intelligent switching harmonic elimination module 120 also includes a voltage terminal module 124, which is used to connect the intelligent switching harmonic elimination module 120 to the open triangle of the voltage transformer cabinet A through a test line.

[0040] It should be noted that the main control module 110 is also used to interact with the human-computer interaction module 170 to obtain operator instructions and display information on the LCD screen 171; interact with the storage module 160 to record a large number of accident event waveforms; and interact with the communication interface module 150 to establish communication with the host computer or background.

[0041] Specifically, the operation steps of the harmonic elimination device 100 of the substation include: first, the device is initialized and self-checked, the decision unit, clock, working mode and parameters of each module of the device are initially set, and the device is self-checked. If the device operates normally, the subsequent steps are executed. If the device is abnormal, the LCD screen 171 displays the fault and lights up the corresponding signal light. Secondly, the parameters are refreshed, and the real-time analog quantity of the characteristic quantity sampling module 130 is obtained and displayed on the LCD screen 171. If the LCD screen 171 cannot display correctly, the corresponding fault is reported and the corresponding signal light is lit. Thirdly, the harmonic elimination algorithm is executed to judge and execute the corresponding command and display the corresponding fault information, and at the same time, the device is queried whether there is a key input, if so, the key command is executed, and the key command is reset after execution. Thirdly, the device is queried whether there is a communication demand, if there is a communication demand, the communication command is executed, and the key command is reset after execution. Finally, the device human-computer interaction module 170 performs corresponding alarms, instructions, records, and displays according to the execution results.

[0042] In summary, in order to solve the huge hidden dangers of the existing power grid harmonic elimination device, the embodiment of the present invention has developed a harmonic elimination device 100 for a substation, which fills the gap of the online harmonic elimination temporary exit system, can well diagnose the resonance type, and adopts the intelligent switching harmonic elimination module 120 to realize the harmonic elimination function, so as to achieve safe and accurate operation. The harmonic elimination device 100 of the present invention has the advantages of portability, accurate diagnosis, safety and controllability. The device adopts a large-capacity rechargeable lithium battery, which is convenient for multi-scene mobile operation; at the same time, the device is equipped with a voltage terminal module 124 and an operation button 172 to quickly realize the access and operation of the harmonic elimination device 100, which perfectly matches the characteristics of the short-term harmonic elimination function of the existing power grid. The device adopts a high-performance main control module 110 and an intelligent switching harmonic elimination module 120, which can quickly and accurately calculate and determine the fault type in the system and eliminate the corresponding resonance. The LCD display 171 and the signal light group 174 can effectively warn the operation and maintenance personnel of the accident type. It is also equipped with a storage module 160 and a panel printer 173, using fault analysis and accident recall. The portability of the device enables it to replace the traditional online detuning device, quickly and accurately make up for the lack of detuning function within the station, and can be used in rotation in various substations, which is of great significance for the efficient suppression of ferromagnetic resonance in substations.

[0043] Figure 5 A flowchart of a method for eliminating harmonics in a substation provided by an embodiment of the present invention is implemented by using the detuning device for a substation in any of the above embodiments, referring to Figure 5 , the detuning methods of substations include:

[0044] S510, acquiring characteristic quantities collected by a characteristic quantity sampling module, wherein the characteristic quantities include an open delta voltage of a voltage transformer cabinet and a zero-sequence current of a voltage transformer cabinet.

[0045] S520: When it is detected that the open delta voltage is greater than or equal to the first voltage threshold and the zero-sequence current is greater than or equal to the first current threshold, it is determined that resonance occurs in the substation, and the thyristor unit is controlled to be turned on.

[0046] It should be noted that if the open triangle voltage is not greater than or equal to the first voltage threshold, it is determined that no ferromagnetic resonance has occurred in the substation, and the main control module can interact with other modules to display the corresponding "open triangle voltage is abnormal but no resonance has occurred" alarm message.

[0047] The first voltage threshold and the first current threshold can be modified by the user according to usage requirements. For example, the first voltage threshold can include 30V, and the first current threshold can include 50mA.

[0048] S530, obtaining the frequency of the open triangle voltage.

[0049] S540, determining the type of resonance occurring in the substation according to the frequency of the open triangle voltage, controlling the conduction of corresponding contacts in the contact unit according to the resonance type, and utilizing the corresponding nonlinear damping resistor in the nonlinear damping resistor unit to achieve detuning of the substation.

[0050] Figure 6 A flowchart of another method for eliminating harmonics in a substation provided by an embodiment of the present invention, referring to Figure 6 , the detuning methods of substations include:

[0051] S610, acquiring characteristic quantities collected by a characteristic quantity sampling module, wherein the characteristic quantities include an open delta voltage of a voltage transformer cabinet and a zero-sequence current of a voltage transformer cabinet.

[0052] S620: When it is detected that the open delta voltage is greater than or equal to the first voltage threshold and the zero-sequence current is greater than or equal to the first current threshold, it is determined that resonance occurs in the substation, and the thyristor unit is controlled to be turned on.

[0053] S630, obtaining the frequency of the open triangle voltage.

[0054] S640, determining the type of resonance occurring in the substation according to the frequency of the open triangle voltage, controlling the conduction of corresponding contacts in the contact unit according to the resonance type, and utilizing the corresponding nonlinear damping resistor in the nonlinear damping resistor unit to achieve detuning of the substation.

[0055] Optionally, based on the above embodiment, step S640 includes:

[0056] S641. When it is detected that the frequency of the open triangle voltage is greater than or equal to the first frequency threshold and less than or equal to the second frequency threshold, it is determined that fundamental frequency resonance occurs in the substation, and the first contact is controlled to be turned on, and the first thermistor is used to achieve detuning of the substation.

[0057] The first frequency threshold and the second frequency threshold can be modified by the user according to usage requirements. For example, the first frequency threshold may include 49 Hz, and the second frequency threshold may include 51 Hz.

[0058] S642: When it is detected that the frequency of the open triangle voltage is less than or equal to the first frequency threshold, it is determined that the substation has frequency division resonance, and the second contact is controlled to be turned on, and the second thermistor is used to achieve detuning of the substation.

[0059] S643. When it is detected that the frequency of the open triangle voltage is greater than or equal to the second frequency threshold, it is determined that high-frequency resonance occurs in the substation, and the third contact is controlled to be turned on, and the third thermistor is used to achieve detuning of the substation.

[0060] Optionally, based on the above embodiment, the characteristic quantity further includes: a loop current of the intelligent switching and harmonic elimination module and a loop temperature of the intelligent switching and harmonic elimination module.

[0061] After step S640, the method further includes:

[0062] S651. When it is detected that the loop current is greater than or equal to the second current threshold or the loop temperature is greater than or equal to the first temperature threshold, the thyristor unit is controlled to be disconnected, and the corresponding contact in the contact unit is controlled to be disconnected, so that the substation exits detuning.

[0063] The second current threshold and the first temperature threshold can be modified by the user according to usage requirements. For example, the second current threshold can include 6A, and the first temperature threshold can include 80°C.

[0064] It can be understood that when the loop current is greater than or equal to the second current threshold or the loop temperature is greater than or equal to the first temperature threshold, it means that the energy generated by the resonance of the substation has been consumed. At this time, the main control module controls the thyristor unit to disconnect, and at the same time controls the corresponding contacts in the contact unit to disconnect, so that the substation exits detuning.

[0065] Optionally, based on the above embodiment, after step S640, the following steps are further included:

[0066] S652. When it is detected that the zero-sequence current is less than or equal to the third current threshold, the thyristor unit is controlled to be disconnected, and at the same time, the corresponding contact in the contact unit is controlled to be disconnected, so that the substation exits detuning; wherein the third current threshold is less than the second current threshold.

[0067] The third current threshold value may be modified by the user according to usage requirements. For example, the third current threshold value may include 30 mA.

[0068] It can be understood that when the zero-sequence current is less than or equal to the third current threshold, it means that the energy generated by the resonance of the substation has been consumed. At this time, the main control module controls the thyristor unit to disconnect, and at the same time controls the corresponding contacts in the contact unit to disconnect, so that the substation exits detuning.

[0069] It should be noted that the main control module can output the fault information and waveform of the judgment result to the human-computer interaction module and activate the alarm signal.

[0070] The detuning method for a substation provided in an embodiment of the present invention is implemented by the detuning device for a substation provided in the above embodiment, and therefore has the same beneficial effects. For matters not described in detail in the embodiment of the present invention, reference may be made to the detuning method for a substation provided in the above embodiment.

[0071] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0072] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A harmonic elimination device for a substation, characterized in that: include: Main control module, intelligent switching and harmonic elimination module and characteristic quantity sampling module; The intelligent switching and harmonic elimination module and the characteristic quantity sampling module are both electrically connected to the main control module; The intelligent switching harmonic elimination module comprises: a nonlinear damping resistor unit, a contact unit and a thyristor unit; the thyristor unit comprises a first thyristor and a second thyristor; The input end of the first thyristor is electrically connected to the first end of the open triangle of the voltage transformer cabinet, the output end of the first thyristor is electrically connected to the first end of the contact unit, the second end of the contact unit is electrically connected to the first end of the nonlinear damping resistor unit, the second end of the nonlinear damping resistor unit is electrically connected to the input end of the second thyristor unit, and the output end of the second thyristor is electrically connected to the second end of the open triangle; The characteristic quantity sampling module comprises an open triangle voltage acquisition unit and a zero-sequence current acquisition unit, the open triangle voltage acquisition unit is connected in parallel with the open triangle, and the zero-sequence current acquisition unit is electrically connected to the neutral point of the open triangle; The control end of the first thyristor, the control end of the second thyristor, the control end of the contact unit, the open triangle voltage acquisition unit and the zero-sequence current acquisition unit are all electrically connected to the main control module.

2. The harmonic elimination device of a substation according to claim 1, characterized in that: The contact unit includes: a first contact, a second contact and a third contact; The first end of the first contact, the first end of the second contact and the first end of the third contact are all electrically connected to the output end of the first thyristor, and the second end of the first contact, the second end of the second contact and the second end of the third contact are all electrically connected to the first end of the nonlinear damping resistor unit; The control end of the first contact, the control end of the second contact, and the control end of the third contact are all electrically connected to the main control module.

3. The harmonic elimination device of a substation according to claim 2, characterized in that: The nonlinear damping resistor unit includes: a first thermistor, a second thermistor and a third thermistor; The first end of the first thermistor is electrically connected to the second end of the first contact unit, the first end of the second thermistor is electrically connected to the second end of the second contact unit, and the first end of the third thermistor is electrically connected to the second end of the third contact unit; the second end of the first thermistor, the second end of the second thermistor and the second end of the third thermistor are all electrically connected to the input end of the second thyristor; The resistance values ​​of the first thermistor, the second thermistor and the third thermistor all vary nonlinearly with temperature; The resistance value of the first thermistor is within a first resistance value interval. When the main control module detects that the frequency of the open triangle voltage is greater than or equal to the first frequency threshold and less than or equal to the second frequency threshold, it is determined that the substation has a fundamental frequency resonance, and the first contact is controlled to be turned on, and the first thermistor is used to achieve detuning of the substation; the resistance value of the second thermistor is within a second resistance value interval. When the main control module detects that the frequency of the open triangle voltage is less than or equal to the first frequency threshold, it is determined that the substation has a frequency division resonance, and the second contact is controlled to be turned on, and the second thermistor is used to achieve detuning of the substation; The resistance of the third thermistor is within a third resistance range. When the main control module detects that the frequency of the open triangle voltage is greater than or equal to a second frequency threshold, it is determined that high-frequency resonance occurs in the substation, and the third contact is controlled to be turned on, and the third thermistor is used to achieve detuning of the substation.

4. The harmonic elimination device of a substation according to claim 1, characterized in that: The open triangle voltage acquisition unit includes a voltage transformer, and the zero-sequence current acquisition unit includes a current probe; The detection end of the voltage transformer is connected in parallel with the open delta, and the signal transmission end of the voltage transformer is electrically connected with the main control module; The detection end of the current probe is electrically connected to the neutral point of the open triangle, and the signal transmission end of the current probe is electrically connected to the main control module.

5. The harmonic elimination device of a substation according to claim 1, characterized in that: The characteristic quantity sampling module also includes: a current transformer and a temperature sensor; The current transformer and the temperature sensor are both electrically connected to the intelligent switching and harmonic elimination module.

6. The harmonic elimination device of a substation according to claim 1, characterized in that: Also includes: Lithium battery charging and power supply module, communication interface module, storage module and human-computer interaction module; The main control module, the characteristic quantity sampling module and the human-computer interaction module are all electrically connected to the lithium battery charging and power supply module; the communication interface module, the storage module and the human-computer interaction module are all electrically connected to the main control module; The human-computer interaction module includes a liquid crystal display screen, operation buttons, a panel printer and a signal light group.

7. A method for eliminating harmonics in a substation, implemented by using the device for eliminating harmonics in a substation as claimed in any one of claims 1 to 6, characterized in that: The detuning method of the substation comprises: Acquire characteristic quantities collected by a characteristic quantity sampling module, wherein the characteristic quantities include an open delta voltage of a voltage transformer cabinet and a zero-sequence current of the voltage transformer cabinet; When it is detected that the open triangle voltage is greater than or equal to a first voltage threshold, and the zero-sequence current is greater than or equal to a first current threshold, it is determined that resonance occurs in the substation, and the thyristor unit is controlled to be turned on; Obtaining the frequency of the open triangle voltage; The resonance type of the substation is determined according to the frequency of the open triangle voltage, and the corresponding contacts in the contact unit are controlled to be turned on according to the resonance type, and the corresponding nonlinear damping resistor in the nonlinear damping resistor unit is used to achieve detuning of the substation.

8. The method for eliminating harmonics in a substation according to claim 7, characterized in that: The step of determining the resonance type of the substation according to the frequency of the open triangle voltage, controlling the corresponding contacts in the contact unit to be turned on according to the resonance type, and using the corresponding nonlinear damping resistor in the nonlinear damping resistor unit to achieve detuning of the substation includes: When it is detected that the frequency of the open triangle voltage is greater than or equal to the first frequency threshold and less than or equal to the second frequency threshold, it is determined that the substation has fundamental frequency resonance, and the first contact is controlled to be turned on, and the first thermistor is used to achieve detuning of the substation; When it is detected that the frequency of the open triangle voltage is less than or equal to the first frequency threshold, it is determined that the substation has frequency division resonance, and the second contact is controlled to be turned on, and the substation is detuned by using the second thermistor; When it is detected that the frequency of the open triangle voltage is greater than or equal to the second frequency threshold, it is determined that high-frequency resonance occurs in the substation, and the third contact is controlled to be turned on, and the third thermistor is used to achieve detuning of the substation.

9. The method for eliminating harmonics in a substation according to claim 7, characterized in that: The characteristic quantity also includes: the circuit current of the intelligent switching harmonic elimination module and the circuit temperature of the intelligent switching harmonic elimination module; After determining the resonance type of the substation according to the frequency of the open triangle voltage, controlling the corresponding contacts in the contact unit to be turned on according to the resonance type, and using the corresponding nonlinear damping resistor in the nonlinear damping resistor unit to achieve detuning of the substation, the method further includes: When it is detected that the loop current is greater than or equal to the second current threshold or the loop temperature is greater than or equal to the first temperature threshold, the thyristor unit is controlled to be disconnected, and the corresponding contact in the contact unit is controlled to be disconnected, so that the substation exits detuning.

10. The method for eliminating harmonics in a substation according to claim 7, characterized in that: After determining the resonance type of the substation according to the frequency of the open triangle voltage, controlling the corresponding contacts in the contact unit to be turned on according to the resonance type, and using the corresponding nonlinear damping resistor in the nonlinear damping resistor unit to achieve detuning of the substation, the method further includes: When it is detected that the zero-sequence current is less than or equal to a third current threshold, the thyristor unit is controlled to be disconnected, and at the same time, the corresponding contact in the contact unit is controlled to be disconnected, so that the substation exits detuning; wherein the third current threshold is less than the second current threshold.

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