Intelligent damping resistor module for anti-resonance and disturbance calculation

Abstract

The utility model discloses an intelligent damping resistor module for anti-resonance and disturbance calculation, which comprises a conventional damping resistor R1 connected in series between a neutral point of a system and the ground, and two ends of the conventional damping resistor R1 are connected in parallel with a self-triggering loop. A switchable damping resistor R2 is further connected between the conventional damping resistor R1 and the ground in series, the two ends of the switchable damping resistor R2 are connected with a controllable trigger loop in parallel, the controlled end of the controllable trigger loop is connected with the output end of a system arc extinction controller, and the input end of the arc extinction controller is connected with a current transformer CT1 used for measuring the current of an arc extinction coil loop. The self-triggering loop is used for preventing resonance of the system when the system operates normally. The controllable trigger loop is used for preventing the system from generating unreal grounding when the single-phase grounding fault disappears and disturbing the system so as to accurately calculate the capacitance current, thereby guaranteeing the stable operation of the system.

Description

Technical Field

[0001] This utility model relates to the technical field of neutral grounding system in power distribution networks, and in particular to a damping resistor module in such a system. Background Technology

[0002] In a neutral-point grounded distribution network system, grounding the neutral point via an arc-suppression coil is a widely used grounding method. During normal system operation, the arc-suppression coil operates near its resonant point. To prevent resonance during normal operation, damping resistors are connected to the system in series or parallel. After the arc-suppression coil is put into operation, the resistance of the damping resistor is a fixed value. When a single-phase ground fault occurs, the arc-suppression controller removes the damping resistor from the system to improve the inductor current compensation capability. However, when the ground fault disappears, if the damping resistor cannot be effectively engaged, the system will exhibit large imbalance and small residual current, making it highly susceptible to illusory grounding.

[0003] As the cable coverage rate increases, the imbalance in the distribution network becomes smaller. After the arc suppression coil is put into the system, the capacitive current cannot be calculated normally through methods such as tap adjustment and tuning, resulting in incorrect capacitive current calculation, poor automatic tracking compensation effect, or even failure to automatically track. Furthermore, after the system ground fault disappears, the inaccurate calculation of the capacitive current will also prevent the damping resistor from being effectively put into operation, affecting the normal operation of the system. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an intelligent damping resistor module for anti-resonance and disturbance calculation, which can improve the calculation accuracy of the capacitor current of the arc suppression controller, thereby accurately controlling the switching of the damping resistor and effectively suppressing the occurrence of illusory grounding faults.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0006] A smart damping resistor module for anti-resonance and disturbance calculation includes a conventional damping resistor R1 connected in series between the system neutral point and ground, and a self-triggering circuit connected in parallel across the two ends of the conventional damping resistor R1; a switchable damping resistor R2 is also connected in series between the conventional damping resistor R1 and ground, and a controllable triggering circuit is connected in parallel across the two ends of the switchable damping resistor R2; the controlled end of the controllable triggering circuit is connected to the output end of the system arc suppression controller, and the input end of the arc suppression controller is connected to a current transformer CT1 for measuring the current in the arc suppression coil circuit.

[0007] The intelligent damping resistance module for preventing resonance and disturbance calculation, the regular damping resistance R1 is provided with two, the switchable damping resistance R2 is connected between the two regular damping resistances R1, the self-triggering loop comprises a self-triggering thyristor KKG1, a self-triggering voltage-dependent resistor RV11 and a self-triggering voltage-dependent resistor RV12, one end of the self-triggering thyristor KKG1 is connected with the regular damping resistance R1 near the neutral point through the self-triggering voltage-dependent resistor RV11, and the other end of the self-triggering thyristor KKG1 is connected with the regular damping resistance R1 of the grounding end through the self-triggering voltage-dependent resistor RV12.

[0008] The intelligent damping resistance module for preventing resonance and disturbance calculation, the controllable trigger loop comprises a controllable loop thyristor KKG2 and two auxiliary nodes FZ, two ends of the controllable loop thyristor KKG2 are connected at two ends of the switchable damping resistance R2 through one auxiliary node FZ respectively, and the controlled end of the auxiliary node FZ is connected with the output end of the arc extinguishing controller.

[0009] The intelligent damping resistance module for preventing resonance and disturbance calculation, the two ends of the auxiliary node FZ are connected in parallel with a controllable loop voltage-dependent resistor.

[0010] Thanks to the above technical scheme, the technical progress achieved by the utility model is as follows.

[0011] The self-triggering loop is used for preventing resonance of the system when the system normally operates, the controllable trigger loop is used for preventing the system from generating illusory grounding when the single-phase grounding fault disappears and for disturbing the system to accurately calculate the capacitor current, thereby guaranteeing stable operation of the system.

[0012] The switchable damping resistance added on the regular damping resistance and the controllable trigger loop connected with the switchable damping resistance can realize switching operation of the switchable damping resistance, the arc extinguishing controller controls the thyristor of the controllable trigger loop to be turned on or turned off by sending and stopping the steady-state pulse signal, so that the switchable damping resistance is put into or withdrawn, and the protection of the system is realized.

[0013] The arc extinguishing controller monitors system parameters in real time, when the zero sequence voltage jumps, the arc extinguishing controller immediately stops sending the pulse signal, controls the switchable damping resistance to be short-circuited and put into for a short time, suppresses system oscillation and avoids occurrence of illusory grounding, when the system returns to normal, the thyristor of the controllable trigger loop is turned on, and the switchable damping resistance is short-circuited and withdrawn from the system, when the arc extinguishing controller monitors that the system imbalance is as low as the calculation precision of the capacitor current of the arc extinguishing controller is not high or the arc extinguishing controller does not calculate, the arc extinguishing controller stops sending the steady-state pulse signal, controls the switchable damping resistance to be put into, generates a large disturbance signal, and after the arc extinguishing controller detects the disturbance signal, the capacitor current is calculated, after the calculation is completed, the arc extinguishing controller resumes sending the instruction to control the thyristor of the controllable trigger loop to be turned on, the switchable damping resistance is short-circuited and withdrawn from the system.

[0014] Therefore, in this invention, when the zero-sequence voltage jumps, a switchable damping resistor is applied to suppress system oscillation and avoid the occurrence of illusory grounding; when the system imbalance is low, the disturbance generated by applying the switchable damping resistor is beneficial to improving the accuracy of the capacitor current calculation of the arc suppression controller, thus making the automatic tracking compensation effect better. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] Figure 2 This diagram illustrates the relationship between the arc suppression controller, the intelligent damping resistor module, and the system described in this utility model.

[0017] Figure 3 This is a schematic diagram illustrating the working principle of this utility model.

[0018] Among them: 1. Conventional damping resistor R1; 2. Self-triggering thyristor KKG1; 3. Self-triggering varistor; 4. Switchable damping resistor R2; 5. Controllable loop thyristor KKG2; 6. Controllable loop varistor; 7. Auxiliary node FZ. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] A smart damping resistor module for anti-resonance and disturbance calculation, its structure is as follows: Figure 1 As shown, it includes a conventional damping resistor R1, a self-triggering circuit, a switchable damping resistor R2, and a controllable triggering circuit.

[0021] The self-triggering circuit is connected in parallel across the two ends of a conventional damping resistor R1 to prevent resonance in the system during normal operation; and to achieve self-triggering when a single-phase ground fault occurs in the system and the self-triggering conditions are met.

[0022] A controllable triggering circuit is connected in parallel across the switchable damping resistor R2 to prevent the system from generating a phantom ground when a single-phase ground fault disappears and to disturb the system in order to accurately calculate the capacitor current, thereby ensuring the stable operation of the system.

[0023] In this invention, two conventional damping resistors R1 are provided, connected in series between the system neutral point and ground, and a switchable damping resistor R2 is connected between the two conventional damping resistors R1.

[0024] The self-triggering circuit includes a self-triggering thyristor KKG1, a self-triggering varistor RV11, and a self-triggering varistor RV12. One end of the self-triggering thyristor KKG1 is connected to a conventional damping resistor R1 near the neutral point via the self-triggering varistor RV11, and the other end of the self-triggering thyristor KKG1 is connected to a conventional damping resistor R1 at the ground terminal via the self-triggering varistor RV12.

[0025] The controllable triggering circuit includes a controllable circuit thyristor KKG2 and two auxiliary nodes FZ. The two ends of the controllable circuit thyristor KKG2 are respectively connected to the two ends of the switchable damping resistor R2 through an auxiliary node FZ. The controlled end of the auxiliary node FZ is connected to the output end of the arc suppression controller.

[0026] The input terminal of the arc suppression controller is connected to the current transformer CT1 to collect the current in the arc suppression coil circuit; at the same time, the arc suppression controller will also collect other analog quantities of the system, including system voltage, zero-sequence voltage, etc.

[0027] The arc suppression controller controls the switching on and off of the switchable damping resistor R2. This invention can also provide real-time feedback on the on / off state of the controllable circuit's silicon controlled rectifier KKG2 to the arc suppression controller to determine whether the switching on / off state of the damping resistor is normal. The relationship between the three is as follows: Figure 2 As shown.

[0028] The working process of this utility model is as follows: Figure 3 As shown, the details are as follows.

[0029] The arc suppression controller collects analog quantities of the system in real time, including arc suppression coil loop current, system voltage, and zero-sequence voltage.

[0030] When the system is running normally, the arc suppression controller continuously sends steady-state pulse signals to control the conduction of the controllable circuit thyristor KKG2, and the switchable damping resistor R2 is short-circuited.

[0031] When the system grounding disappears, the zero-sequence voltage of the system will jump. At this time, the arc suppression controller immediately stops sending steady-state pulse signals, controls the controllable circuit thyristor KKG2 of the controllable trigger circuit to turn off, and the switchable damping resistor R2 is briefly connected to increase the system damping, suppress system oscillation, and avoid the occurrence of phantom grounding. After the system oscillation disappears, the arc suppression controller resumes sending steady-state pulse signals after a delay, and the switchable damping resistor R2 is taken out of the system.

[0032] The arc suppression controller also monitors system parameters to analyze whether the system unbalanced voltage meets the requirements for calculating the system capacitance current. If so, the arc suppression controller operates normally and does not send instructions to the intelligent damping resistor module. If not, meaning the arc suppression controller's capacitance current calculation is inaccurate or not calculated at all, it stops sending steady-state pulse signals, controls the auxiliary node of the controllable trigger circuit to open, turns off the controllable circuit thyristor KKG2, and engages the switchable damping resistor, generating a large disturbance. After detecting the disturbance signal, the arc suppression controller performs capacitance current calculation. The calculation process is as follows:

[0033] System unbalanced voltage E0 and system capacitive reactance X c Assuming no change before and after the automatic tracking adjustment of the arc suppression coil, the zero-sequence voltage is U before the damping resistor is switched on. 01 The loop current is I 01 At this point, due to the small system imbalance, the error in the system capacitor current value calculated by the arc suppression controller is relatively large. After the switchable damping resistor is engaged, the zero-sequence voltage is U. 02 The loop current is I 02 At this point, the system imbalance is caused by a sudden change in loop impedance, resulting in a disturbance. The arc suppression controller calculates the system capacitive current based on the disturbance amounts ΔU and ΔI. That is:

[0034]

[0035] After the calculation is completed, the arc suppression controller resumes sending steady-state pulse signals, controlling the closing of the auxiliary node of the controllable trigger circuit, turning on the thyristor, and short-circuiting the switchable damping resistor R2 to remove it from the system. The arc suppression coil can perform automatic tracking compensation, and the arc suppression coil operates near the resonant point.

[0036] In this invention, a controllable loop varistor RV21 is connected in parallel across the two ends of auxiliary node FZ1, and a controllable loop varistor RV22 is connected in parallel across the two ends of auxiliary node FZ2. When the arc suppression controller malfunctions and there is no pulse signal output, or when a controllable trigger circuit malfunctions and the thyristor cannot conduct, the controllable loop varistor will self-trigger when it reaches the threshold start-up voltage, causing the controllable loop thyristor KKG2 to conduct, short-circuiting the switchable damping resistor R2, preventing the switchable damping resistor R2 from overheating, and thus providing protection.

Claims

1. An intelligent damping resistance module for anti-resonance and disturbance calculation, comprising a conventional damping resistance R1 connected in series between a system neutral point and ground, a self-triggering loop being connected in parallel across the conventional damping resistance R1; characterized in that: The conventional damping resistor R1 is also connected in series with the ground, and a switchable damping resistor R2 is connected in parallel with the two ends of the switchable damping resistor R2, a controllable trigger circuit is connected in parallel with the two ends of the switchable damping resistor R2, the controlled end of the controllable trigger circuit is connected with the output end of the system arc-extinguishing controller, and the input end of the arc-extinguishing controller is connected with a current transformer CT1 for measuring the arc-extinguishing coil loop current.

2. An intelligent damping resistance module for anti-resonance and disturbance calculation according to claim 1, characterized in that: The conventional damping resistor R1 is provided with two, and the switchable damping resistor R2 is connected between the two conventional damping resistors R1; the self-triggering circuit comprises a self-triggering thyristor KKG1, a self-triggering voltage-dependent resistor RV11 and a self-triggering voltage-dependent resistor RV12, one end of the self-triggering thyristor KKG1 is connected with the conventional damping resistor R1 near the neutral point through the self-triggering voltage-dependent resistor RV11, and the other end of the self-triggering thyristor KKG1 is connected with the conventional damping resistor R1 of the ground end through the self-triggering voltage-dependent resistor RV12.

3. The intelligent damping resistance module for anti-resonance and disturbance calculation according to claim 1, characterized in that: The controllable trigger circuit comprises a controllable circuit thyristor KKG2 and two auxiliary nodes FZ, the two ends of the controllable circuit thyristor KKG2 are respectively connected with the two ends of the switchable damping resistor R2 through one auxiliary node FZ, and the controlled end of the auxiliary node FZ is connected with the output end of the arc-extinguishing controller.

4. The intelligent damping resistance module for anti-resonance and disturbance calculation according to claim 3, characterized in that: The two ends of the auxiliary node FZ are connected in parallel with a controllable circuit voltage-dependent resistor.

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