Resonance elimination circuit, method and device

Abstract

The invention discloses a resonance elimination circuit, method and device, and relates to the technical field of circuits, and the circuit comprises a controller, a resonance elimination resistor and a switching circuit. Two ends of the resonance elimination resistor are respectively connected with the neutral point of the voltage transformer and the ground. The controller controls the switching circuit to be switched off when ferromagnetic resonance is detected, so that the resonance elimination resistor is connected to suppress resonance; after the fault disappears, the control switch is switched on, and the neutral point is directly grounded. The controller compares the neutral point current with a first threshold value to determine resonance generation, and determines fault disappearance when the current is smaller than a second threshold value. And when the resonance elimination resistor is a variable resistor, the controller adjusts the resistance value according to the current change rate and a pre-learned mapping relation. The switching circuit can adopt a switching tube or a relay, and the controller realizes switching by controlling the switching tube to be turned off or a relay coil to be powered off. The circuit can rapidly suppress ferromagnetic resonance, guarantee system stability and improve fault processing efficiency.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a harmonic suppression circuit, method, and apparatus. Background Technology

[0002] In power systems, the 35kV and below systems of the power grid adopt an ungrounded neutral point operation mode. In this system, in order to effectively suppress ferroresonance and ensure the safe and stable operation of the power system, a harmonic suppression device needs to be installed at the neutral point of the voltage transformer. This is a conventional measure taken to solve the ferroresonance problem during the operation of this system.

[0003] Currently, the primary harmonic suppression devices installed in the power grid are mainly based on varistor structures. Under normal operating conditions, the grounding resistance of such devices ranges from several thousand ohms to tens of thousands of ohms. This resistance value causes the neutral point of the voltage transformer to be in an ineffectively grounded state.

[0004] When there is unbalanced current in a three-phase voltage transformer, the neutral point is not effectively grounded, which will cause voltage imbalance on the low-voltage bus. This will have an adverse effect on the voltage stability of the power system and may cause some electrical equipment to malfunction. Summary of the Invention

[0005] This application provides a harmonic suppression circuit, method, and apparatus that can maintain voltage stability in a power system.

[0006] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application provides a harmonic suppression circuit, including: a controller, a harmonic suppression resistor, and a switching circuit; The first end of the harmonic suppression resistor is used to connect to the neutral point of the voltage transformer, and the second end of the harmonic suppression resistor is used to ground. The first terminal of the switching circuit is connected to the first terminal of the harmonic suppression resistor, and the second terminal of the switching circuit is connected to the second terminal of the harmonic suppression resistor. The controller is used to control the switching circuit to turn off when a ferroresonance fault occurs in the voltage transformer.

[0007] Optionally, the controller is also configured to control the switching circuit to turn on when the ferroresonant fault of the voltage transformer disappears.

[0008] Optionally, the controller is specifically configured to acquire a first current at the neutral point, and if the first current is greater than or equal to a first threshold, determine that the voltage transformer has experienced a ferroresonant fault.

[0009] Optionally, the controller is further configured to determine that the ferroresonant fault of the voltage transformer has disappeared if the first current is less than a second threshold; the second threshold is less than the first threshold.

[0010] Optionally, the harmonic suppression resistor is a variable resistor, and the controller is further configured to obtain a first rate of change of the first current and adjust the resistance value of the harmonic suppression resistor according to the first rate of change.

[0011] Optionally, the controller is specifically configured to determine a first adjustment coefficient corresponding to the first change rate based on the mapping relationship between the reference change rate and the participation adjustment coefficient obtained in advance, and to adjust the resistance value of the harmonic elimination resistor using the first adjustment coefficient.

[0012] Optionally, the switching circuit includes a switching transistor, wherein a first terminal of the switching transistor is a first terminal of the switching circuit, and a second terminal of the switching transistor is a second terminal of the switching circuit; The controller is specifically used to control the switching transistor to turn off.

[0013] Optionally, the switching circuit includes a relay; the relay includes a first contact, a second contact, and a coil, the first contact being a first terminal of the switching circuit, and the second contact being a second terminal of the switching circuit; when the coil is energized, the first contact and the second contact are connected, and when the coil is de-energized, the first contact and the second contact are disconnected; The controller is specifically used to de-energize the coil.

[0014] Secondly, this application provides a harmonic suppression method applied to a harmonic suppression circuit, the harmonic suppression circuit including a controller, a harmonic suppression resistor, and a switching circuit; the first terminal of the harmonic suppression resistor is used to connect to the neutral point of a voltage transformer, and the second terminal of the harmonic suppression resistor is used to ground; the first terminal of the switching circuit is connected to the first terminal of the harmonic suppression resistor, and the second terminal of the switching circuit is connected to the second terminal of the harmonic suppression resistor; including: When a ferroresonance fault occurs in the voltage transformer, the controller controls the switching circuit to shut down.

[0015] Optionally, the method further includes: The controller controls the switching circuit to conduct when the ferroresonant fault of the voltage transformer disappears.

[0016] Optionally, the controller determines that a ferroresonant fault has occurred, including: The controller acquires the first current at the neutral point. If the first current is greater than or equal to a first threshold, it determines that the voltage transformer has a ferroresonant fault.

[0017] Optionally, the method further includes: If the first current is less than the second threshold, the controller determines that the ferroresonant fault of the voltage transformer has disappeared; the second threshold is less than the first threshold.

[0018] Optionally, the method further includes: The harmonic suppression resistor is a variable resistor, and the controller obtains the first rate of change of the first current; the resistance value of the harmonic suppression resistor is adjusted according to the first rate of change.

[0019] Optionally, the controller adjusts the resistance value of the harmonic suppression resistor, including: The controller determines a first adjustment coefficient corresponding to the first change rate based on the pre-learned mapping relationship between the reference change rate and the participation adjustment coefficient, and adjusts the resistance value of the harmonic elimination resistor using the first adjustment coefficient.

[0020] Optionally, the switching circuit includes a switching transistor, wherein a first terminal of the switching transistor is a first terminal of the switching circuit, and a second terminal of the switching transistor is a second terminal of the switching circuit, comprising: The controller controls the switching transistor to turn off.

[0021] Optionally, the switching circuit includes a relay; the relay includes a first contact, a second contact, and a coil, the first contact being a first terminal of the switching circuit, and the second contact being a second terminal of the switching circuit; when the coil is energized, the first contact and the second contact are connected; when the coil is de-energized, the first contact and the second contact are disconnected, including: The controller de-energizes the coil.

[0022] Thirdly, this application provides a harmonic suppression device, including any of the harmonic suppression circuits optional in the first aspect.

[0023] Fourthly, this application provides a computing device, including a memory and a processor; The memory stores one or more computer programs, the one or more computer programs including instructions; when the instructions are executed by the processor, the computing device performs the method as described in any one of the second aspects.

[0024] Fifthly, this application provides a computer-readable storage medium for storing a computer program for performing the method as described in any one of the second aspects.

[0025] As can be seen from the above technical solution, this application has at least the following beneficial effects: In this application, the harmonic suppression circuit and device achieve significant technical advantages and practical value through innovative design. Its core lies in the collaborative architecture of the controller, harmonic suppression resistor, and switching circuit. This architecture can quickly control the switching circuit to turn off when ferroresonance occurs in the voltage transformer, allowing the harmonic suppression resistor to be connected to the neutral point circuit to suppress resonance. Simultaneously, it can promptly turn the switching circuit back on after the fault disappears, restoring the low-impedance grounding state required for normal operation. This effectively avoids the problem of ineffective neutral point grounding caused by fixed impedance in traditional devices, significantly reducing the risk of low-voltage bus voltage imbalance. Through an intelligent judgment mechanism based on the neutral point current threshold and rate of change, combined with the dynamic resistance adjustment of the variable resistor and the pre-learned mapping relationship, the device can accurately identify faults and adapt to different resonance scenarios. This significantly improves the response speed and accuracy of ferroresonance suppression, reduces the probability of voltage transformer damage due to resonance and primary fuse burnout, and extends the equipment's service life. Meanwhile, the switching circuit is compatible with various forms such as switching transistors and relays, enhancing its applicability in systems of different voltage levels. The real-time monitoring and data storage functions provide a reliable basis for fault analysis and operation and maintenance optimization, reducing equipment operation and maintenance costs and improving the overall stability and economy of power system operation.

[0026] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0027] Figure 1 A schematic diagram of a harmonic suppression circuit provided in an embodiment of this application; Figure 2 A schematic diagram of a harmonic suppression circuit based on a variable resistor provided in an embodiment of this application; Figure 3 A schematic diagram of a harmonic suppression circuit based on a switching transistor provided in an embodiment of this application; Figure 4 A schematic diagram of a relay-based harmonic suppression circuit provided for an embodiment of this application; Figure 5A schematic diagram of yet another harmonic suppression circuit provided in an embodiment of this application; Figure 6 This is a schematic diagram of a computing device provided in an embodiment of this application. Detailed Implementation

[0028] The terms "first," "second," and "third," etc., used in this application specification and accompanying drawings are used to distinguish different objects, not to limit a specific order.

[0029] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0030] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the related technologies is given first: A voltage transformer converts high voltage to low voltage proportionally to provide signals for measuring instruments and protection devices.

[0031] The neutral point is the common point of a star connection in a three-phase power system.

[0032] Ferromagnetic resonance occurs when the system parameters are matched, the core of the voltage transformer may saturate, triggering nonlinear resonance and causing an abnormal increase in the neutral point voltage.

[0033] The harmonic suppression circuit consumes resonant energy and suppresses overvoltage when connected to the neutral point circuit.

[0034] After a ferroresonance occurs, traditional devices require hundreds of milliseconds to respond, resulting in a long overvoltage duration. Traditional varistor-type harmonic suppressors maintain high impedance during normal operation, which may cause three-phase voltage imbalance, and the non-effective grounding of the neutral point leads to zero-sequence voltage deviation.

[0035] In view of this, this application provides a harmonic suppression circuit. This circuit addresses the problems of ineffective neutral grounding (leading to voltage imbalance on the low-voltage bus), limited ferroresonant suppression effect, and lack of fault monitoring capability in traditional varistor-type primary harmonic suppression devices in 35kV and below ungrounded neutral point power grid systems. This invention innovatively introduces power electronic devices into the harmonic suppression circuit, and achieves precise suppression of ferroresonant resonance and traceable fault analysis by dynamically adjusting the neutral grounding state and integrating full-scenario monitoring functions.

[0036] To make the technical solution of this application clearer and easier to understand, a harmonic suppression circuit provided in an embodiment of this application will be described below with reference to the accompanying drawings. Figure 1As shown in the figure, this figure is a schematic diagram of a harmonic suppression circuit provided in an embodiment of this application.

[0037] The first terminal of the harmonic suppression resistor is used to connect to the neutral point of the voltage transformer, and the second terminal is used for grounding. The first terminal of the switching circuit is connected to the first terminal of the harmonic suppression resistor, and the second terminal of the switching circuit is connected to the second terminal of the harmonic suppression resistor. The controller is used to control the switching circuit to turn off when a ferroresonance fault occurs in the voltage transformer. The controller is also used to control the switching circuit to turn on when the ferroresonance fault of the voltage transformer disappears.

[0038] The harmonic suppression resistor 101 is directly connected between the neutral point S and ground, forming an energy dissipation path during a fault. The switching circuit 201 is connected in parallel with the harmonic suppression resistor 101, and the on / off control determines whether the harmonic suppression resistor 101 is connected to the circuit.

[0039] During normal operation, switch circuit 201 is turned on (equivalent to a short circuit), harmonic suppression resistor 101 is bypassed, and neutral point S is directly grounded through low impedance (switch circuit 201). This eliminates the three-phase voltage imbalance problem caused by the high impedance grounding of traditional varistor and reduces the loss during normal system operation (switch on resistance is usually <0.1Ω).

[0040] In the ferroresonant state, the controller shuts off the switching circuit 201, and the harmonic suppression resistor 101 is connected to the neutral point S grounding circuit. The high-resistance harmonic suppression resistor 101 dissipates resonant energy and suppresses overvoltage. The switching circuit 201 uses power electronic devices (such as IGBTs), with a response time of <100ns, which is much faster than traditional mechanical switches.

[0041] The controller is specifically used to obtain the first current at the neutral point. If the first current is greater than or equal to a first threshold, it is determined that the voltage transformer has a ferroresonant fault.

[0042] The first current refers to the current between the neutral point S of the voltage transformer and ground, that is, the current flowing through the harmonic suppression resistor 101 (or the switching circuit 201), which is read using an A4 ammeter.

[0043] When ferroresonance occurs, the saturation of the voltage transformer core causes a sharp drop in magnetizing inductance, forming a resonant circuit with the system capacitance. The initial current can surge by tens or even hundreds of times. For example, the initial current of a 10kV system under normal operation is approximately 30mA, but when frequency subtraction resonance occurs, the initial current can jump to over 2A.

[0044] The first current is the most direct physical quantity reflecting ferromagnetic resonance. Its variation amplitude is positively correlated with the resonance intensity and can be used as the core criterion for fault triggering.

[0045] The controller has a pre-set current threshold, also known as the first threshold. When the first current is greater than or equal to the first threshold, ferroresonance is determined to occur. The maximum value of the neutral point S current during normal operation is calculated based on system parameters (such as voltage level, line length, voltage transformer model, etc.). The first threshold is usually set to 5-10 times the maximum normal current value (for example, if the maximum normal current value is 50mA, the first threshold can be set to 0.5A).

[0046] The controller is also configured to determine that the ferroresonant fault of the voltage transformer has disappeared if the first current is less than a second threshold; the second threshold is less than the first threshold.

[0047] The second threshold is a preset current threshold value used by the controller to determine that the ferroresonant fault has been eliminated, and its value is less than the first threshold (for example, if the first threshold is 2A, the second threshold can be set to 0.5A). When the monitored first current of the neutral point S is continuously less than the second threshold, the controller determines that the resonant fault has disappeared, and then controls the switch circuit 201 to be turned on again, restoring the normal operation state of the voltage transformer neutral point S being directly grounded.

[0048] The fading of ferroresonance is a gradual process; the current will not drop instantly from "far exceeding the first threshold" to a normal level, but will gradually decay. If the first threshold is used directly as the recovery criterion, current fluctuations (such as a brief drop below the first threshold but not truly stabilizing) may cause frequent switching of the switching circuit 201, affecting system stability. Therefore, the second threshold is usually set to 1 / 3 to 1 / 5 of the first threshold.

[0049] As the harmonic suppression resistor 101 consumes the resonant energy, the first current gradually decreases. When the first current is less than the second threshold and remains stable, the controller confirms that the resonance has completely disappeared, controls the switch circuit 201 to conduct, and restores the neutral point S to direct ground.

[0050] like Figure 2 As shown in the figure, this figure is a schematic diagram of a harmonic suppression circuit based on a variable resistor provided in an embodiment of this application.

[0051] exist Figure 2 In the circuit, the harmonic elimination resistor 101 is a variable resistor 1011, and the controller is also used to obtain the first rate of change of the first current; and adjust the resistance value of the harmonic elimination resistor according to the first rate of change.

[0052] The first rate of change is the rate of change of the neutral point S current with time, which directly reflects the development trend of ferromagnetic resonance, and its expression is:

[0053] in, The first rate of change, This represents the current at time t. The sampling period.

[0054] If the first rate of change is positive and large (e.g., above 100 A / s), it indicates that the resonance is rapidly intensifying and the energy accumulation rate is fast; if the first rate of change decreases (e.g., from 50 A / s to 10 A / s), it indicates that the resonance is stabilizing or beginning to subside and the energy accumulation is slowing down.

[0055] The controller dynamically adjusts the resistance value of the variable resistor 1011 according to the following rules: When the first rate of change is large (resonance develops rapidly), the resistance value of the harmonic suppression resistor 101 needs to be increased. A higher resistance value can consume the electromagnetic energy of the resonant circuit more quickly (according to Joule's law, the larger the resistance, the greater the power loss under the same current), thereby quickly curbing the intensification of resonance; when the first rate of change is small (resonance slows down or disappears), the resistance value of the harmonic suppression resistor 101 needs to be decreased to avoid excessively high resistance values ​​causing the residual energy in the circuit to be released too slowly after normal harmonic suppression, or causing unnecessary impedance effects on the normal operation of the system; when the first rate of change is close to 0 (resonance disappears), the resistance value can be adjusted to the minimum (or restored to the initial value), and in conjunction with the conduction of the switching circuit 201, ensure that the neutral point S is grounded with low impedance.

[0056] Specifically, the controller is used to determine the first adjustment coefficient corresponding to the first change rate based on the mapping relationship between the reference change rate and the participation adjustment coefficient obtained in advance, and to adjust the resistance value of the harmonic elimination resistor using the first adjustment coefficient.

[0057] Based on historical power grid fault records, this study analyzes the characteristics of the first rate of change and the optimal resistance adjustment strategy under different types of resonance (such as frequency division, fundamental frequency, and high-frequency resonance). Various resonance scenarios are simulated using power system simulation software (such as PSCAD and MATLAB / Simulink), and the correspondence between the first rate of change and the resistance value is extracted. A functional relationship between the first rate of change and the adjustment coefficient is fitted to form a mapping table or model. The final mapping relationship can be expressed as:

[0058] in, Indicates the adjustment factor. The adjustment factor indicates the rate of change and is used to correct the reference resistance value of the harmonic suppression resistor 101 (e.g., if the initial resistance value is 500Ω and the adjustment factor is 1.5, the actual resistance value is adjusted to 750Ω).

[0059] For example, the mapping relationship of a certain 10kV system might be:

[0060] when At that time, the mapping table displays the adjustment coefficient. ;when hour, .

[0061] The controller drives the variable resistor 1011 through a PWM (Pulse Width Modulation) signal or a digital potentiometer to smoothly adjust the resistance from the current value to the target value, avoiding transient shocks caused by sudden changes.

[0062]

[0063] in, This indicates the adjusted resistance value. This indicates the resistance value before adjustment.

[0064] like Figure 3 As shown in the figure, this figure is a schematic diagram of a harmonic suppression circuit based on a switching transistor provided in an embodiment of this application.

[0065] exist Figure 3 In this circuit, the switching circuit is a switching transistor, the first terminal of the switching transistor is the first terminal of the switching circuit, and the second terminal of the switching transistor is the second terminal of the switching circuit; the controller is specifically used to control the switching transistor to turn off.

[0066] When the system is running normally, the controller outputs a high level (e.g., +15V), driving the switching transistor 2011 to fully conduct. The on-resistance of the switching transistor 2011 is approximately 0.05Ω. The neutral point S is grounded through a low impedance, and the harmonic suppression resistor 101 is bypassed. This eliminates the voltage imbalance problem caused by traditional high-impedance grounding.

[0067] When the system experiences ferroresonance, the neutral point S current (the first current) increases sharply (usually exceeding the first threshold, such as rising from the normal milliampere level to several amperes or even higher). The controller, detecting this anomaly through the A4 ammeter, immediately outputs a low-level signal (such as 0V or -5V) to the drive circuit of the 2011 switching transistor. The drive circuit quickly removes the forward bias voltage from the 2011 switching transistor, causing it to switch from the on state to the off state. This process has an extremely short response time.

[0068] After the switching transistor 2011 is turned off, its equivalent impedance instantly increases to an extremely high level (approximately an open circuit). The previously bypassed harmonic suppression resistor 101 is then connected to the loop between the neutral point S and ground. At this time, the harmonic suppression resistor 101, as a high-impedance component, suppresses the further development of resonance by consuming resonant energy (according to Joule's law, the higher the resistance value, the greater the energy loss under the same current), causing the voltage and current at the neutral point S to drop rapidly.

[0069] In this state, the connection of the harmonic suppression resistor 101 not only effectively curbs the impact of overvoltage and overcurrent on the voltage transformer (avoiding primary fuse burnout or equipment damage), but also breaks the inductor-capacitor parameter matching condition required for ferroresonance through its high impedance characteristics, fundamentally weakening the resonance intensity. Once the neutral point S current is monitored to drop below the second threshold (confirming that the resonance has completely disappeared), the controller outputs a high level again, driving the switching transistor 2011 to conduct again, restoring the normal operating state of the neutral point S with low impedance grounding, and completing the closed-loop control of "fault suppression-system recovery".

[0070] like Figure 4 As shown in the figure, this figure is a schematic diagram of a relay-based harmonic suppression circuit provided in an embodiment of this application.

[0071] exist Figure 4 In this circuit, the switching circuit is a relay, which includes a first contact, a second contact, and a coil. The first contact is the first terminal of the switching circuit, and the second contact is the second terminal of the switching circuit. When the coil is energized, the first contact and the second contact are connected, and when the coil is de-energized, the first contact and the second contact are disconnected. The controller is specifically used to control the coil to lose power.

[0072] When the system is in normal operation (coil energized, contacts closed), the controller outputs a high level, which energizes the coil of relay 2012 through the drive circuit (e.g., 12V voltage applied across the coil). The coil generates a magnetic field, attracting the armature and causing the first and second contacts to close (conduct). At this time, the contact resistance is extremely low (typically <0.1Ω). The conducting contacts of the harmonic suppression resistor 101 are bypassed, and the neutral point S of the voltage transformer is directly grounded through a low impedance (contact), avoiding the voltage imbalance caused by the high impedance of traditional varistors.

[0073] When the system is in a ferroresonant state (coil de-energized, contacts closed), the controller detects that the neutral point S current is greater than or equal to the first threshold and determines that a fault has occurred. The controller outputs a low level, cutting off the coil power supply (coil de-energized), the magnetic field disappears, the armature resets under the action of spring force, and the first and second contacts separate (closed). The harmonic suppression resistor 101 is connected to the loop between the neutral point S and ground, dissipating the resonant energy through high impedance and suppressing the development of ferroresonant resonance.

[0074] When the system is in a fault recovery state (the coil is re-energized), when the controller detects that the current at the neutral point S is less than the second threshold (resonance disappears), it outputs a high level again to energize the coil, closes the contacts, and restores the neutral point S to direct grounding, completing the "normal-fault-normal" switching closed loop.

[0075] like Figure 5 As shown, this figure is a schematic diagram of another harmonic suppression circuit provided in an embodiment of this application. Figure 5 In addition, two modules have been added: a data monitoring and storage module, and a fault intelligent analysis and human-computer interaction module.

[0076] The data monitoring and storage module primarily monitors and stores data from four ammeters and one voltmeter, enabling continuous 24-hour monitoring of voltage and current, and storing at least one month's worth of data. A high-precision voltmeter V and an ammeter A4 are directly installed in the circuit between the neutral point S of the voltage transformer and ground, acquiring the voltage and current at neutral point S in real time. Three current transformers are connected in series at the primary side of the three-phase voltage transformer (near the neutral point S) to monitor the primary current of each of phases AN, BN, and CN. Specifically, ammeter A1 is installed at the AN terminal, ammeter A2 at the BN terminal, and ammeter A3 at the CN terminal to detect the primary current of each phase.

[0077] Data is stored cyclically in chronological order, with older data automatically overwritten to ensure that the latest 30 days of complete records are retained in real time. When a current / voltage exceeds a preset threshold, an "event marker" is triggered, and data for that time period (5 minutes before and after the event) is stored in a separate partition without being overwritten, for fault tracing.

[0078] The monitoring data is transmitted in real time to the fault intelligent analysis and human-machine interaction module. For example, by the rate of change of the neutral point S and the harmonic components of the voltage, the ferroresonance and single-phase grounding faults can be distinguished (the neutral point S voltage contains a 25Hz frequency component during resonance, and the fundamental frequency is dominant during grounding).

[0079] When the neutral point S current is detected to be greater than or equal to the first threshold, a "resonance warning" signal is sent to the controller, triggering the shutdown action of the switching circuit 201. After the fault subsides, the monitoring data showing that the neutral point S current is less than the second threshold is used as the criterion for the controller to resume normal operation. This breaks through the limitation of traditional devices that "only monitor fault conditions".

[0080] Based on the above description, this application has the following beneficial effects: This harmonic suppression circuit and device achieve significant technical advantages and practical value through innovative design. Its core lies in the collaborative architecture of the controller, harmonic suppression resistor, and switching circuit. This architecture can quickly control the switching circuit to shut off when ferroresonance occurs in the voltage transformer, allowing the harmonic suppression resistor to be connected to the neutral point S circuit to suppress resonance. Simultaneously, it can promptly turn the switching circuit back on after the fault disappears, restoring the low-impedance grounding state required for normal operation. This effectively avoids the problem of ineffective neutral point S grounding caused by fixed impedance in traditional devices, significantly reducing the risk of low-voltage bus voltage imbalance. Through an intelligent judgment mechanism based on the neutral point S current threshold and change rate, combined with the dynamic resistance adjustment of the variable resistor and a pre-learned mapping relationship, the device can accurately identify faults and adapt to different resonance scenarios. This significantly improves the response speed and accuracy of ferroresonance suppression, reduces the probability of voltage transformer damage due to resonance and primary fuse burnout, and extends equipment lifespan. Meanwhile, the switching circuit is compatible with various forms such as switching transistors and relays, enhancing its applicability in systems of different voltage levels. The real-time monitoring and data storage functions provide a reliable basis for fault analysis and operation and maintenance optimization, reducing equipment operation and maintenance costs and improving the overall stability and economy of power system operation.

[0081] The above text combined Figures 1 to 5 The harmonic suppression circuit provided in the embodiments of this application has been described in detail. The harmonic suppression method provided in the embodiments of this application will be described below with reference to the accompanying drawings.

[0082] This application embodiment also provides a harmonic suppression method applied to a harmonic suppression circuit, the harmonic suppression circuit including a controller, a harmonic suppression resistor, and a switching circuit; the first terminal of the harmonic suppression resistor is used to connect to the neutral point of a voltage transformer, and the second terminal of the harmonic suppression resistor is used to ground; the first terminal of the switching circuit is connected to the first terminal of the harmonic suppression resistor, and the second terminal of the switching circuit is connected to the second terminal of the harmonic suppression resistor; the method includes: When a ferroresonance fault occurs in the voltage transformer, the controller controls the switching circuit to shut down.

[0083] Optionally, the method further includes: When the ferroresonant fault of the voltage transformer disappears, the controller controls the switching circuit to turn on.

[0084] Optionally, the controller determines that a ferroresonant fault has occurred, including: The controller acquires the first current at the neutral point. If the first current is greater than or equal to a first threshold, it determines that the voltage transformer has a ferroresonant fault.

[0085] Optionally, the method further includes: If the first current is less than the second threshold, the controller determines that the ferroresonant fault of the voltage transformer has disappeared; the second threshold is less than the first threshold.

[0086] Optionally, the method further includes: The harmonic suppression resistor is a variable resistor, and the controller obtains the first rate of change of the first current; the resistance value of the harmonic suppression resistor is adjusted according to the first rate of change.

[0087] Optionally, the controller adjusts the resistance value of the harmonic suppression resistor, including: The controller determines a first adjustment coefficient corresponding to the first change rate based on the pre-learned mapping relationship between the reference change rate and the participation adjustment coefficient, and adjusts the resistance value of the harmonic elimination resistor using the first adjustment coefficient.

[0088] Optionally, the switching circuit includes a switching transistor, wherein a first terminal of the switching transistor is a first terminal of the switching circuit, and a second terminal of the switching transistor is a second terminal of the switching circuit, comprising: The controller controls the switching transistor to turn off.

[0089] Optionally, the switching circuit includes a relay; the relay includes a first contact, a second contact, and a coil, the first contact being a first terminal of the switching circuit, and the second contact being a second terminal of the switching circuit; when the coil is energized, the first contact and the second contact are connected; when the coil is de-energized, the first contact and the second contact are disconnected, including: The controller de-energizes the coil.

[0090] This application also provides a harmonic suppression device, which includes the harmonic suppression circuit described in the above embodiments.

[0091] This application also provides a computing device. For example... Figure 6 As shown in the figure, this is a schematic diagram of a computing device provided in an embodiment of this application. The computing device 700 includes a bus 701, a processor 702, a communication interface 703, and a memory 704. The processor 702, the memory 704, and the communication interface 703 communicate with each other via the bus 701.

[0092] The 701 bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 6The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0093] The processor 702 can be any one or more of the following processors: central processing unit (CPU), graphics processing unit (GPU), microprocessor (MP), or digital signal processor (DSP).

[0094] The communication interface 703 is used for communication with external devices.

[0095] Memory 704 may include volatile memory, such as random access memory (RAM). Memory 704 may also include non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0096] The memory 704 stores executable code, and the processor 702 executes the executable code to perform the aforementioned harmonic elimination method.

[0097] This application also provides a computer-readable storage medium. The computer-readable storage medium can be any available medium that a computing device can store, or a data storage device such as a data center containing one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive). The computer-readable storage medium includes instructions that instruct a computing device to perform the aforementioned harmonic cancellation method.

[0098] This application also provides a computer program product comprising one or more computer instructions. When the computer instructions are loaded and executed on a computing device, all or part of the processes or functions described in this application are generated.

[0099] The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, or data center to another website, computer, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0100] When the computer program product is executed by a computer, the computer performs any of the aforementioned harmonic elimination methods. The computer program product can be a software installation package; when any of the aforementioned harmonic elimination methods is required, the computer program product can be downloaded and executed on the computer.

[0101] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0102] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application.

Claims

1. A harmonic suppression circuit, characterized in that, include: Controller, harmonic suppression resistor, switching circuit; The first end of the harmonic suppression resistor is used to connect to the neutral point of the voltage transformer, and the second end of the harmonic suppression resistor is used to ground. The first terminal of the switching circuit is connected to the first terminal of the harmonic suppression resistor, and the second terminal of the switching circuit is connected to the second terminal of the harmonic suppression resistor. The controller is used to control the switching circuit to turn off when a ferroresonance fault occurs in the voltage transformer.

2. The harmonic suppression circuit according to claim 1, characterized in that, The controller is also used to control the switching circuit to turn on when the ferroresonance fault of the voltage transformer disappears.

3. The harmonic suppression circuit according to claim 1 or 2, characterized in that, The controller is specifically used to acquire the first current of the neutral point, and if the first current is greater than or equal to a first threshold, it is determined that the voltage transformer has a ferroresonant fault.

4. The harmonic suppression circuit according to claim 3, characterized in that, The controller is further configured to determine that the ferroresonant fault of the voltage transformer has disappeared if the first current is less than a second threshold; the second threshold is less than the first threshold.

5. The harmonic suppression circuit according to claim 1, characterized in that, The harmonic suppression resistor is a variable resistor, and the controller is further configured to obtain a first rate of change of the first current and adjust the resistance value of the harmonic suppression resistor according to the first rate of change.

6. The harmonic suppression circuit according to claim 5, characterized in that, The controller is specifically used to determine a first adjustment coefficient corresponding to the first change rate based on the mapping relationship between the reference change rate and the participation adjustment coefficient obtained in advance, and to adjust the resistance value of the harmonic elimination resistor using the first adjustment coefficient.

7. The harmonic suppression circuit according to claim 1, characterized in that, The switching circuit includes a switching transistor, the first terminal of which is the first terminal of the switching circuit, and the second terminal of which is the second terminal of the switching circuit. The controller is specifically used to control the switching transistor to turn off.

8. The harmonic suppression circuit according to claim 1, characterized in that, The switching circuit includes a relay; the relay includes a first contact, a second contact, and a coil, the first contact being a first terminal of the switching circuit, and the second contact being a second terminal of the switching circuit; when the coil is energized, the first contact and the second contact are connected, and when the coil is de-energized, the first contact and the second contact are disconnected; The controller is specifically used to de-energize the coil.

9. A harmonic elimination method, characterized in that, The method is applied to a harmonic suppression circuit, which includes a controller, a harmonic suppression resistor, and a switching circuit. The first terminal of the harmonic suppression resistor is connected to the neutral point of a voltage transformer, and the second terminal of the harmonic suppression resistor is grounded. The first terminal of the switching circuit is connected to the first terminal of the harmonic suppression resistor, and the second terminal of the switching circuit is connected to the second terminal of the harmonic suppression resistor. When a ferroresonance fault occurs in the voltage transformer, the controller controls the switching circuit to shut down.

10. A harmonic suppression device, characterized in that, Includes the harmonic suppression circuit as described in any one of claims 1 to 8.

Images