5769 results about "Overvoltage" patented technology

The invention discloses a sampling implementation method and system suitable for motor protection quick response, belongs to the technical field of motor protection, and can increase the sampling frequency and improve the quick response of motor fault protection. Comprising the steps that motor phase current and bus voltage are collected, after anti-aliasing filtering is conducted, parallel sampling is conducted through a main ADC module and a redundant ADC module which are independently configured, and the following operations are synchronously executed based on a double-buffer-area framework: in a first buffer area, a compensation coefficient updating period is dynamically adjusted, and convergence is restrained; in the second buffer area, generating a voltage gradient prediction sequence, and compensating data abrupt change; when the harmonic frequency spectrum amplitude or the voltage gradient prediction sequence exceeds the limit, an oversampling mode is triggered, a redundant ADC module is allocated to load a multi-order digital filter, and an independent hardware acceleration unit is started to process harmonic compensation and gradient prediction in parallel; and generating a dynamic safety envelope, and if the gradient extreme value in the preset continuous window breaks through the safety envelope, generating an overvoltage fault signal.

The invention relates to the technical field of power electronics, in particular to a control method for a low-voltage intelligent reactive compensation system of a submerged arc furnace. Comprising the following steps: acquiring three-phase voltage, current, power factor, harmonic content and temperature parameters of the low-voltage side of the submerged arc furnace through a sensor network; the load fluctuation of the submerged arc furnace in the future 1-5 minutes is predicted based on a deep learning algorithm, and a compensation demand pre-judgment value is generated; according to a load prediction result and a real-time working condition, performing dynamic switching from three modes of fixed compensation, grouped switching and continuous adjustment; harmonic component dynamic tracking compensation is carried out by combining an active power filter (APF) and a static var generator (SVG); the system overvoltage, overcurrent and temperature parameters are monitored in real time, and a grading protection mechanism is triggered and fed back to the compensation strategy adjusting module. The invention provides a control method for a low-voltage intelligent reactive compensation system of a submerged arc furnace so as to improve the response speed of the system, prolong the service life of equipment and guarantee the electric energy quality of a power grid.

The invention relates to the technical field of power grid monitoring, and discloses a voltage sensor multi-parameter real-time monitoring method and device in an Internet of Things environment. According to the method, real-time voltage fluctuation data of a target area is acquired by deploying a multi-channel voltage sensor array and is transmitted to an edge computing node; dynamic feature extraction is executed in the edge nodes, and a multi-dimensional feature matrix containing voltage fluctuation ratio, harmonic distortion and phase deviation features is generated; identifying voltage sag, overvoltage and harmonic resonance event characteristics based on an anomaly detection model; spatial correlation modeling is carried out in combination with power grid topological structure parameters, the coupling strength of adjacent sensor node parameters is calculated, and a multi-parameter correlation map containing event propagation paths and influence ranges is generated; inputting the voltage into a diagnosis model to generate a power grid state diagnosis report, and dynamically adjusting the sampling frequency and filtering parameters of the voltage sensor according to the power grid state diagnosis report. According to the method, real-time monitoring and analysis of multiple parameters of the power grid can be realized, and comprehensive support is provided for power grid state evaluation.

The invention discloses a new energy bearing capacity evaluation method considering transient overvoltage constraint, and belongs to the technical field of energy safety. The invention discloses a new energy bearing capacity evaluation method considering transient overvoltage constraint. The method comprises the following steps: S1, calculating a short-circuit ratio of a multi-new energy station sending end system; s2, calculating the transient overvoltage of a new energy station node in the sending end system; and S3, constructing a power grid new energy bearing capacity evaluation model considering the transient overvoltage constraint. According to the new energy bearing capacity evaluation method considering the transient overvoltage constraint, the mathematical relation among the transient overvoltage amplitude, the system short-circuit ratio and the active power of the new energy station is used as a main line, and the system short-circuit ratio is used as an intermediate quantity; a mathematical expression of a new energy station node transient overvoltage amplitude and new energy station active power is established, and a power grid new energy bearing capacity evaluation model considering multiple new energy station transient overvoltage constraints is constructed, so that it is ensured that an optimal new energy station output value can be obtained, and safe operation of a power grid is ensured.

The invention relates to the technical field of battery state monitoring, in particular to an intelligent online capacity checking management system for a storage battery pack, which comprises a jump sensing module, a lag correlation module, a starting point confirmation module, a state diagnosis module and a correction output module. According to the invention, the method achieves the precise recognition of a voltage hysteresis effect through the positioning of the difference value of a current sudden change point, the tracking of a fluctuation convergence interval, the construction of a dynamic sudden change buffer structure, the enhancement of the capturing capability of a key change behavior, the extraction of a response time point in combination with the change trend of a voltage derivative, and the combined binding of a charge state based on the voltage difference value and current sampling. The real-time performance and the pertinence of capacity evaluation are improved, the sudden change period is identified through the charge state difference value, a synchronous mark is established through voltage stability analysis, correction mapping is carried out according to the state difference, a capacity correction path with continuity, traceability and dynamic adaptability is formed, and the precision and the stability of capacity management of the storage battery pack are effectively improved.

The invention relates to the technical field of electronic circuit detection, in particular to a detection method for checking abnormal work of a lamp, which comprises the following steps: acquiring the consistency of a lighting state and voltage, extracting abnormal response, checking power supply connection and checking non-response, monitoring and controlling the relationship between output and current action starting, and analyzing response continuity. And detecting branch voltage difference change and direction, monitoring voltage jump and current response starting point performance, extracting response data, and obtaining a classification result. According to the invention, through cooperative detection of voltage and current response behaviors, in combination with path voltage difference direction change and time sequence characteristics, a load abnormal response section is identified step by step, the abnormal state identification capability is enhanced, an action time sequence cross validation mode is adopted to replace a traditional static judgment process, misjudgment interference is reduced, and manual intervention requirements are reduced; therefore, the detection process is more continuous, the related operation is universal, the method can be suitable for various lamp structures, the troubleshooting precision is improved, and the execution cost is controlled at the same time.

The invention provides a fault ride-through control method and a fault ride-through control system for a grid-forming converter, which are characterized in that the current of the grid-forming converter under an asymmetric fault is controlled by adopting a negative-sequence current reference generation strategy aiming at an inner ring of a controller, and negative-sequence reactive current is injected into a power grid; adopting a partial sequence current amplitude limiting strategy to control the maximum phase current amplitude of the injected asymmetric current not to exceed an amplitude limiting value; controlling the boundary of an active reference value by adopting an active reference value amplitude limiting strategy for an active synchronization ring; a synchronous damping link is adopted to enhance damping in power angle swing; for a reactive voltage loop, a reactive voltage variable coefficient control strategy is adopted to control the output of the maximum reactive current; and an internal potential locking strategy is adopted to suppress overvoltage. According to the invention, negative-sequence reactive power is provided, and overcurrent of each phase is avoided; the power angle characteristic is improved, and the transient stability is improved; stable transient voltage support is provided in a current output capability range; and after the fault is recovered, the voltage of the converter grid-connected point is smoothly recovered.

The invention discloses a control method and system for an active equalization lithium iron phosphate hybrid battery device. The method comprises the following steps: full charge correction triggering: starting an active equalization program when the SOC of a battery pack reaches a threshold value; a low-current active equalization strategy is adopted, and charges are continuously transferred; performing dynamic voltage difference threshold control and real-time monitoring: acquiring the voltage of each single battery at intervals, calculating the voltage standard deviation sigma in the module, and if the voltage standard deviation sigma is greater than 30mV, judging that abnormal voltage difference exists; grading response: when the voltage difference between the single batteries exceeds 50mV, immediately stopping the equalization operation, and triggering an overvoltage / undervoltage protection mechanism; and when the voltage difference is between 30mV and 50mV, the equalizing current is reduced to 0.02 C, and if the voltage difference is not recovered to a safe range, the equalizing operation is terminated. According to the method, the active equalization program can be accurately started, capacity calibration is carried out to correct the capacity deviation, and meanwhile, the voltage difference of each single battery is synchronously monitored, so that the equalization efficiency and precision of the battery pack are remarkably improved.

The invention discloses a decoupling control method and system for a matrix motor with harmonic suppression capability, and belongs to the technical field of motor driving systems, and the method comprises the steps: building a matrix motor current loop mathematical model which considers a DC disturbance term and an AC disturbance term at the same time; based on the matrix motor current loop mathematical model, establishing a self-adaptive quasi-resonance extended state observer which simultaneously considers direct current disturbance observation and alternating current disturbance observation and performs self-adaptive adjustment on control parameters; the direct current and alternating current lumped disturbance of a matrix motor current loop is observed in real time through an adaptive quasi-resonance extended state observer; compensating the observed direct current and alternating current lumped disturbance in a forward controller of the current loop and obtaining a voltage control quantity; and controlling the matrix motor through a voltage vector space transformation and SVPWM modulation method according to the voltage control quantity. The method is improved and optimized based on an existing matrix motor vector control system, and the system does not need to be modified on a large scale.

The invention provides a transient overvoltage risk assessment method, device and equipment for an AC / DC system containing high-proportion new energy, and a storage medium. Relates to the technical field of power systems and automation thereof. The method comprises the following steps: modeling a power system into a discrete nonlinear power system based on phase change measurement unit data, constructing a state space, introducing a Koopman operator to determine an observation function, and establishing a dynamic time sequence track prediction model based on the observation function to output a predicted dynamic time sequence track; an Informer model is constructed, in response to an input predicted dynamic time sequence track, feature weights are distributed through a ProbSparse self-attention mechanism, hierarchical feature down-sampling is performed by using a distillation mechanism, and a predicted transient voltage amplitude is output; and quantifying the transient overvoltage risk level according to the predicted transient voltage amplitude. According to the method, the problems of low isolated time section feature prediction precision and poor long-sequence dynamic evolution feature evaluation timeliness in the prior art are solved.

The embodiment of the invention provides a closed-loop control method for power driving and protection, and the method comprises the steps: constructing a voltage feedback type circuit through a high-speed operational amplifier, and forming a closed-loop gain structure through a feedback network of the voltage feedback type circuit; the load current of the output end of the voltage feedback type circuit is monitored in real time, and when the load current exceeds a first set threshold value, a protection mechanism is triggered to turn off the output stage; the power-on surge current is limited through the soft start control circuit; phase information of a load reflection coefficient is obtained, an inductance / capacitance combination of the variable dynamic impedance matching network is selected according to phase information table look-up, inductance / capacitance parameters are switched through a relay, and the transmission standing-wave ratio between the power amplifier and a load is optimized; monitoring the temperature of the radiating fin of the power tube, and dynamically adjusting the resistance value of the feedback network; and performing cooperative control of short-circuit protection, over-temperature protection and surge suppression according to the priority. According to the embodiment of the invention, the performance bottleneck in a load fluctuation scene is broken through.

The invention discloses a linearity closed-loop optimization method for a semiconductor gas sensor with adjustable voltage dynamic compensation, which relates to the technical field of gas detection and comprises the following steps: controlling the semiconductor gas sensor to start in a clean air environment, outputting an initial test voltage sequence through a voltage regulator, the method comprises the steps of collecting sensor reference resistance under different voltages, screening out initial working voltage with the minimum resistance fluctuation quantity, synchronously collecting initial environment temperature and humidity, and calibrating the sensor reference resistance based on preset temperature and resistance coefficients and humidity and resistance coefficients to obtain initial reference resistance. By dynamically adjusting the working voltage and combining real-time compensation on the environment temperature and humidity, the interference of environment factor fluctuation on the resistance characteristic of the sensitive material can be continuously counteracted, so that the linear relation between the output signal of the sensor and the target gas concentration is kept stable, the dynamic optimization of the linearity in a complex environment is realized, and the sensitivity of the sensor is improved. And more reliable basic data is provided for gas concentration detection in an industrial scene.

The invention provides a power system voltage control method and device based on dynamic steady state collaborative correction, and the method comprises the steps: building an electromagnetic transient model for a preset voltage node in electromagnetic transient simulation software PSCAD, simplifying a power grid with the electrical distance to a target region exceeding a preset distance into a dynamic Thevenin equivalent model, initializing load flow calculation in the BPA to obtain a dynamic-steady state hybrid model; updating dynamic Thevenin equivalent parameters of the power system in real time according to the data of the phasor measurement unit of the power system, and synchronizing the dynamic Thevenin equivalent parameters to the BPA; based on the dynamic-steady state hybrid model, the transient overvoltage of the power system is suppressed within the time shorter than the first preset duration, and the steady state voltage of the power system is optimized within the time shorter than the second preset duration in combination with wide-area coordination control, so that the parameter bidirectional correction of the dynamic and steady state models is realized, and the head end voltage prediction error is reduced. And the voltage control robustness is improved.

The invention relates to the technical field of power system monitoring, and provides a power grid data fault diagnosis method and device based on an intelligent power monitoring instrument, and the method comprises the steps: collecting the operation data of a power grid through the intelligent power monitoring instrument, and generating a fault feature vector containing the multi-dimensional feature parameters of voltage, current and power factor; matching and comparing the feature vector with a preset fault criterion; determining a specific fault type based on a comparison result of the characteristic parameters and a threshold value, including identifying voltage abnormity through a voltage deviation rate, identifying harmonic exceeding through a current harmonic total distortion rate, and identifying a three-phase imbalance fault through a three-phase imbalance degree; for judgment of the three-phase unbalance degree, mean square error statistic calculation is adopted, and a safety coefficient is introduced for threshold comparison; and the fault influence priority is evaluated by quantifying the degree of deviation of each characteristic parameter from the threshold. The fault diagnosis efficiency and reliability can be improved, and intelligent decision support is provided for safe operation of a power grid.

The invention discloses a capacitive voltage transformer for a gas insulated substation, which comprises a capacitive voltage divider and an electromagnetic unit, the capacitive voltage divider comprises a high-voltage capacitor C1 and a medium-voltage capacitor, the medium-voltage capacitor comprises a medium-voltage capacitor C21 and an externally connected medium-voltage capacitor C22, and the capacitance of the medium-voltage capacitor C22 is greater than that of the medium-voltage capacitor C21; the electromagnetic unit is connected with the capacitive voltage divider, an intermediate transformer and a compensation reactor are arranged in the electromagnetic unit, a full-shielding high-voltage shielding cover is arranged outside a high-voltage coil of the intermediate transformer, a damper and an overvoltage protector are arranged outside the electromagnetic unit, and the damper and the overvoltage protector are placed in an external junction box. The problem that in the prior art, an extra-high voltage transformer is low in lightning impulse overvoltage tolerance capacity is solved, the impulse overvoltage tolerance capacity is improved, and the breakdown risk is reduced.

The invention discloses a generator access control method of an energy storage power generation system. The method comprises the following steps: connecting a generator to an alternating current side of an energy storage converter through a control switch; when the energy storage converter is in an off-grid state, if the total power supply amount of the energy storage converter meets the load requirement, the generator is disconnected with the load through the control switch, and at the moment, the energy storage converter carries out loading independently; if the total power supply quantity of the energy storage converter does not meet the load requirement, judging the output power of the generator; if the output power of the generator is not overloaded relative to the load demand, the control switch is closed to enable the generator to be loaded independently, and the energy storage converter seals waves; otherwise, the control switch is closed to enable the energy storage converter and the generator to be jointly loaded. The method has the advantages that the energy storage converter is subjected to wave sealing after the generator is connected into the system, power can be prevented from being accumulated on the bus for a long time, and the overvoltage risk of the bus is avoided.

The invention relates to the technical field of power distribution network fault early warning systems and methods, in particular to an intelligent power distribution network fault early warning system and method based on the Internet of Things, and the system comprises a sensing unit, a data processing unit, a data analysis unit, a fault early warning unit, a monitoring management unit, and a personnel inspection subsystem unit. The sensing unit is used for installing a current sensor, a voltage sensor, a temperature sensor and a humidity sensor at key node positions of a transformer, a switch cabinet and a line of the power distribution network, the current sensor is used for monitoring the current in the line in real time, the voltage sensor is used for monitoring the voltage value, and the temperature sensor is used for monitoring the operating temperature of equipment; faults are analyzed and judged from multiple angles, misjudgment and missed judgment are reduced, whether fault hidden dangers exist or not is judged more accurately, the operation state of equipment is evaluated in real time through monitoring of the Internet of Things, the frequency of manual inspection is appropriately reduced, the labor cost is saved, and the resource utilization efficiency is improved.

A crosslinked polyethylene cable is widely applied to a modern power grid, but in the manufacturing and laying process, certain microdefects are inevitably caused in the cable, the cable is corroded by power frequency voltage and different substances in soil during operation, and the microdefects are eroded by water to gradually induce water branch defects. Some water branches grow along the direction of the electric field force and gradually derive into electric branches under the action of overvoltage, and finally the cable insulation layer is broken down. An existing microcapsule type self-repairing material is limited by a triggering mode, is single in function and harsh in triggering condition, cannot perform self-repairing on various defects such as mechanical damage, electric tree branches, water tree branches and micropores, and only can perform single-time repairing, namely, the problems that multiple-time repairing cannot be performed, the repairing efficiency is low and the like exist. Therefore, it is necessary to develop a microcapsule / crosslinked polyethylene composite insulating material with multiple and multiple self-repairing capabilities, and a method for fundamentally exploring and prolonging the service life of the insulating material is provided.

The invention provides a device for inhibiting drain-source overvoltage and overcurrent through active gate drive of a silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), aiming at solving the problem of voltage or current overshoot caused by circuit parasitic parameters in a high-speed switching process of the SiC MOSFET and simultaneously considering the switching speed and energy loss balance. According to the device, drain-source voltage vdc and direct-current bus voltage of the SiC MOSFET are collected to serve as feedback signals, and gate driving voltage and equivalent gate resistance are dynamically adjusted; in a key stage (a Miller plateau switching-on period and a voltage rising period switching-off period) of a switch transient state, a gate resistance network is switched through a logic control circuit, and suppression of drain current overshoot and drain-source voltage overshoot is realized. Simulation verification shows that the device can reduce voltage overshoot by 20%-30% and current overshoot by 25%-60%, only a single voltage feedback channel is needed, the cost is obviously lower than that of a traditional multi-signal acquisition active gate driving scheme, and the device is suitable for a high-efficiency SiC MOSFET power converter.

The invention discloses an intelligent self-adaptive suppression method for oscillation of a data-driven SVG (static var generator) grid-connected system. Obtaining the capacitor voltage of the direct current side of the SVG and the actual voltage and the actual current of the grid connection point of the SVG, and respectively calculating the active power output by the SVG and the voltage amplitude output by the SVG according to the actual voltage and the actual current; a current reference value is generated through a voltage outer loop; the active power output by the SVG, the voltage amplitude output by the SVG and the voltage of the direct current side of the SVG are input into a DeePC controller to be processed, and an additional current reference value is obtained; and then the current error is obtained by adding the current reference value output by the voltage outer loop and subtracting the actual current, and then the current error is input to the voltage inner loop for processing to obtain a modulation wave voltage amplitude signal. According to the method, the oscillation of the converter grid-connected system can be suppressed under the condition that the dynamic characteristics of the converter and the conditions of the power grid are changed, and the problems of insufficient fixed structure and parameter sensitivity of the traditional SVG are solved.

The invention relates to the technical field of power systems, and discloses a voltage regulation system of reactive power compensation equipment, which is characterized in that harmonic interference is filtered and eliminated through a voltage reactive power sensing unit, and accurate power grid parameters are acquired; a load trend pre-judgment unit analyzes the historical load curve and the real-time change trend to generate a future pre-judgment signal; the dynamic compensation calculation unit combines the current power grid state with the prediction to calculate the optimal compensation capacity and generate a switching instruction, after the hybrid switching actuator receives the instruction, a thyristor is triggered firstly to realize inrush current-free conduction, a contactor is switched to maintain low power consumption after the current is stable, and meanwhile, the compensation state monitoring unit performs closed-loop adjustment on parameter deviation, so that the optimal compensation capacity is obtained. The multi-dimensional protection unit prevents overvoltage, overcurrent and overheating, the double-path power supply guarantees continuous operation when the main power supply is abnormal, the intelligent communication unit realizes data uploading and remote cooperation, quick response switching of reactive compensation equipment and guarantee of safety of a large-scale power grid are realized, and inrush current impact in the switching process is effectively inhibited.

The invention provides an impedance scanning device based on network side voltage dynamic compensation under a three-phase voltage imbalance working condition, and relates to the technical field of new energy station power electronic converter topology and control, the device comprises a three-phase rectifier, a direct current bus capacitor, an inverter, a voltage compensation device, a frequency sweeping device, a circuit breaker and a series transformer part, the three-phase rectifier is connected in series with inverters of the voltage compensation device and the frequency sweep device, a secondary side of a series transformer of the voltage compensation device is connected in series with a network side, a secondary side of a series transformer of the frequency sweep device is connected in series with a grid-connected point, and a primary side of the series transformer is connected to the inverters and is coupled to a secondary side of the series transformer; according to the device, the power grid side voltage is rectified through the voltage compensation unit and is compensated to the grid side after being subjected to single-stage inversion transformation, voltage compensation is achieved through the energy of a power grid when the voltage is unbalanced, and an external energy source or an interference source does not need to be introduced. After compensation, the accuracy of the frequency sweeping result is obviously improved.

In certain aspects, a voltage regulator includes a pass transistor coupled between an input of the voltage regulator and an output of the voltage regulator, and an amplifier having a first input coupled to a reference voltage, a second input coupled to the output of the voltage regulator via a feedback path, and an output. The voltage regulator also includes a voltage booster coupled between the output of the amplifier and a gate of the pass transistor. In certain aspects, the voltage booster includes a first capacitor and a second capacitor for double charge pumping. In certain aspects, a control circuit of the voltage booster is coupled to a voltage source that is independent of an output voltage of the amplifier.

The invention relates to the technical field of power electronic driving control, in particular to a driving system and method for an ultrasonic air pump, and the system comprises a control signal generation module which is used for generating a control signal; the voltage superposition driving module is coupled to the control signal generation module and is used for superposing and lifting the driving voltage according to the control signal and executing reversing operation, and the reversing operation comprises forward driving and reverse driving; the driving frequency adjusting module is coupled to the control signal generating module and is used for adjusting the driving frequency and speed of the ultrasonic air pump based on the control signal; and the working circuit protection module is coupled to the voltage superposition driving module and is used for setting dead time between forward driving and reverse driving to prevent short circuit. According to the invention, the dependence of the ultrasonic air pump on an independent high-voltage power supply and how to realize high-voltage alternating driving through voltage superposition and avoid the risk of bridge arm direct connection and resonance mismatch under the constraint of a low-voltage power supply are effectively solved.

The present application provides a converter and a chopper transistor blocking control method therefor. According to the chopper transistor blocking control method, when switching transistors in a converter need to be blocked, switching transistors in a primary side circuit connected to a transformer of the converter are blocked, and switching transistors in a secondary side circuit are blocked when the current on a branch where a secondary side winding in the transformer is located is zero, or batch blocking of the switching transistors in the secondary side circuit is completed after the current on the branch where the secondary side winding is located recirculates to zero, thereby avoiding overvoltage damage to the switching transistors caused by the current on the branch where the secondary side winding is located recirculating by means of the junction capacitance of the switching transistors in the secondary side circuit.

The invention belongs to the field of overvoltage protection, and relates to an overvoltage stabilizing and protecting device which comprises a data acquisition operation module, a control logic module, a display module, an overvoltage protecting assembly and a high-voltage vacuum circuit breaker or an electric isolation handcart structure. The real-time monitoring and protection of the working state of the overvoltage protection assembly are realized; through the arrangement of the high-voltage circuit breaker or the electric isolation handcart, when the overvoltage protection assembly is detected to be abnormal, the connection between the overvoltage protection assembly and the high-voltage bus can be rapidly cut off, so that the system safety is ensured; the device integrates a transient fault recording function and can capture wave map data before and after a power frequency overvoltage fault of the system; the overvoltage protection assembly in the device adopts a geometric center air cooling heat dissipation mode, the fan is quick in starting response, the operating temperature of the overvoltage protection assembly is greatly reduced, the operating time of the overvoltage protection assembly can be effectively prolonged, and the device adopts an integrated modular structural design, so that the operation safety, the maintenance and the management are greatly facilitated.

The invention discloses an insulation state fusion detection method, system, medium and equipment under transient impact in a cable operation process, and the method comprises the steps: synchronously collecting a transient impact signal and a partial discharge signal of a cable under the transient impact effect; performing time-frequency domain separation on the acquired transient impact signal and the partial discharge signal to obtain a transient impact component and a partial discharge component after separation; when it is detected that the amplitude of the transient impact signal exceeds a preset threshold value, a partial discharge detection window is started, and whether a partial discharge signal exists or not is detected in the window period; if a partial discharge signal is detected, multi-dimensional characteristic parameters of the partial discharge signal are extracted, a state vector is constructed in combination with environmental parameters, the state vector is input into a pre-trained machine learning model, and a cable insulation state grade is output; if the partial discharge signal is not detected, performing inversion calculation on the transient impact signal based on a transmission line model, and reconstructing an overvoltage waveform; and extracting propagation characteristic parameters according to the reconstructed overvoltage waveform, and judging the insulation defect type according to the propagation characteristic parameters.

The invention discloses a reactive voltage bimodal control method and system suitable for a new energy power station, and belongs to the technical field of power system voltage control. The invention provides a dual-stage control optimization mechanism based on cooperation of a distributed phase modifier and a static var compensator in order to solve the problems of difficult steady-state voltage regulation and transient voltage instability of a new energy power station caused by wind-light output fluctuation and system short-circuit capacity reduction. According to the method, in steady-state operation, minimization of grid-connected point voltage deviation and maximization of dynamic reserve capacity of a phase modifier are taken as targets, reactive power output of two types of equipment is optimally distributed, and a proper amount of dynamic margin is reserved to support transient requirements; when it is detected that the voltage sag exceeds a safety threshold value, a transient response mode is immediately switched to, that is, phase modifier strong excitation control is activated, and reactive power output, reduced due to low-voltage limitation, of the static reactive power compensator is compensated; and when the voltage enters a recovery stage, triggering the phase modifier to reduce the output in advance through a pre-action instruction, and delaying to recover the steady state mode after the switching of the static var compensator is completed. A double safety protection mechanism is embedded in the whole control process, whether the grid-connected point voltage is in a safety interval or not is verified in real time, and the minimum operation interval of the switching equipment is forced to be executed. Simulation results show that the method can remarkably improve the voltage operation index of the new energy power station, the steady-state voltage fluctuation amplitude is greatly reduced, the transient fault recovery time is obviously shortened, the overvoltage peak value is effectively restrained to be within a safe range, and the industrial problem that the steady-state adjustment precision and the transient supporting capacity cannot be both considered by single reactive power equipment is solved.

According to the cable multi-parameter fusion sensor and method, in the cable multi-parameter fusion sensor, a shielding shell is of an open-close type metal annular structure; the zero-flux sensor module is arranged on the inner layer of the shielding shell so as to detect a cable sheath ring current signal; the pulse current sensor module is arranged on the outer side of the zero-flux sensor module so as to detect a cable partial discharge pulse current signal and an overvoltage impact current signal; the magnetic shielding layer is arranged between the zero-flux sensor module and the pulse current sensor module to shield low-frequency magnetic field interference; the zero magnetic flux sensor module and the pulse current sensor module share the shielding shell to form an electromagnetic shielding structure.

The present invention belongs to the field of smart grids, and relates to a DC voltage adaptive coordinated control system and method under fault of a VSC-HVDC receiving-end power grid. The present invention checks the MSR and compares it with the expected fastest fault clearance time to provide key activation conditions for the active power control of an SEC. When DC overvoltage is prevented, the active power regulation of the SEC and a dynamic brake resistor is reduced by optimizing the control activation thresholds and reference values of the SEC and a REC.