84 results about "Voltage phasors" patented technology

The invention discloses a non-contact electric power parameter measurement method, system and device, and a storage medium. The method comprises the steps of obtaining a first output voltage signal and a second output voltage signal generated by induction of a space electric field around a to-be-measured wire; establishing an equation set of a to-be-measured voltage phasor based on the first output voltage signal and the second output voltage signal, and solving the equation set of the to-be-measured voltage phasor to obtain a parameter of the to-be-measured voltage; acquiring a magnetic field measurement signal generated by a space magnetic field around the to-be-measured wire; and establishing an equation set of the current to be measured according to the magnetic field measurement signal, and solving the equation set of the current to be measured to obtain parameters of the current to be measured, thereby effectively solving the problem that the gain and the phase shift are unknown after the probe is connected.

The invention discloses a low-voltage distribution area topology identification method, system and device and a storage medium, and the method comprises the following steps: deploying a synchronous measurement unit in a low-voltage distribution area, and obtaining the outgoing line current phasor and voltage phasor data with a synchronous time scale of a whole network; constructing an incoming line and outgoing line current phasor set, and performing adaptive descending sorting according to amplitudes; determining that the nodes corresponding to the incoming line current phasors and the found nodes corresponding to the one or more outgoing line current phasors are in a father-son relationship, and iterating the process until all sets are empty, thereby completing the identification of the topological relationship of the power distribution side; and according to the equipment number contained in the obtained voltage phasor data, determining a meter box connected with the user electricity meters, and then clustering the user electricity meters connected to the same meter box according to the voltage phase angle to obtain the connection phase sequence of each user electricity meter. The problem of key information missing is solved from a data source, and accurate and efficient identification of topology is realized by fusing physical constraints.

The invention relates to the technical field of line fault analysis, in particular to a high-voltage line fault identification method based on phasor analysis, which comprises the following steps of: performing multi-time window nesting decomposition on voltage phasors and current phasors acquired in the operation process of a high-voltage line, extracting a phasor dynamic response sequence, and calculating the phasor dynamic response sequence; identifying a main disturbance mechanism characteristic triggered by a fault, and constructing a main disturbance mechanism type label; a driving response dominant phasor disturbance factor is identified, a phasor factor mapping graph is constructed, factor stripping operation is executed, and a dominant purification phasor set is generated; and performing phase evolution analysis on the dominant purification phasor set, and determining a fault initial phase transition boundary and a cross-phase offset trend. According to the method, the stability and the physical consistency of identification are ensured, and the finally output fault type and phase structured result not only has clear logic traceability, but also highly meets the requirements of dispatching automation and quick response of a protection system.

The invention provides a new energy station high-voltage voltage transformer error evaluation method and system, and the method comprises the steps: collecting the voltage phasors of all measurement nodes in a preset time period at a transformer substation and a new energy station at the same time, obtaining the equipment parameters of a voltage transformer and the line parameters between the measurement nodes, and constructing a measurement data set; the method comprises the following steps: constructing a corresponding adjacency matrix and a node characteristic matrix by extracting line impedance and node working condition characteristics based on a power system line topological structure and data in a measurement data set, and obtaining a time sequence diagram structure data set according to the adjacency matrix and the node characteristic matrix; constructing a graph neural network, and training the graph neural network based on the time sequence graph structure data set; and inputting the voltage phasor of each measurement node, and based on the output result of the trained graph neural network, judging the state of the voltage transformer through a preset threshold value. According to the scheme, online evaluation of the error state of the voltage transformer can be realized, and the accuracy and interpretability of error evaluation are improved.

The invention relates to the field of electric power measurement, and provides a voltage transformer error evaluation method and device, electronic equipment and a storage medium, and the method comprises the steps: collecting the voltage phasor information of a measurement node in a preset time window, and obtaining the reference technical parameters of a voltage transformer corresponding to the measurement node; feature extraction based on a sliding window is carried out, sequence diagram structural features are obtained in combination with an adjacent matrix, and the adjacent matrix is constructed based on network topology and line electrical parameters of a power system; error estimation is carried out through a trained error estimation model based on the time sequence diagram structure features, an error estimation value is obtained, and the error estimation model is obtained by training a graph neural network model based on historical voltage phasor information and corresponding error labels; and performing error state evaluation based on the error estimation value. According to the method, the device, the electronic equipment and the storage medium provided by the invention, online continuous evaluation of the voltage transformer error is realized, and the limitations of long period and high cost of a traditional offline verification method are broken through.

The invention discloses a power grid power flow real-time calculation and state estimation method and system based on a PMU, and belongs to the technical field of electric measurement and electric fault positioning. The method comprises the following steps: synchronously measuring electrical variables, including a voltage phasor and a current phasor, of a power grid node through PMU equipment to obtain synchronous phasor data, and verifying time and topology consistency; the power grid observability grade is judged based on PMU configuration node distribution corresponding to the verified electric measurement data; directly generating a real-time state estimation result through linear calculation based on PMU electric measurement data if the whole domain is observable; and if a part is observable, fusing PMU and SCADA data, carrying out nonlinear state estimation through a weighted least square method, distributing a high weight for the PMU electrical measurement data, and dynamically adjusting the SCADA weight to suppress bad data. According to the method, through observability adaptive judgment, the precision and efficiency of state estimation are improved, a data basis is provided for power grid fault positioning, and the method is suitable for practical application scenes of various PMU coverage degrees.

The invention provides a self-networking control protection method and device for a grid-connected energy storage converter, and a medium. The method comprises the following steps: acquiring electrical quantities of a grid-connected point and a direct current side, establishing a short-circuit capacity estimation value and a positive and negative zero sequence model, and generating a voltage phasor reference; generating a given frequency and a given voltage according to the power and frequency droop and the reactive power and voltage droop; generalized impedance shaping is executed in a control loop, and virtual impedance and selective filtering are configured according to frequency bands; completing grid connection or re-connection according to a sequence of frequency slope, phase angle slow alignment and voltage amplitude gradual combination based on a grid connection point reference phasor; setting positive-sequence, negative-sequence and zero-sequence fault current upper limits and a time sequence template in the symmetric component domain; and outputting the given frequency, the given voltage, the sequence component limit value and the protection state instruction to a converter power bridge driving and grid-connected switch control interface. According to the invention, phase-lock-free grid-connected synchronization, unified control protection switching, sequence component controlled fault current and weak grid stable operation can be realized.

The invention discloses a flywheel energy storage active phase modulation control method, system and device and a medium, and the method comprises the following steps: collecting multi-source power data of a power grid, and obtaining preprocessed phasor data; inputting the preprocessed phasor data into a first network model, and predicting a voltage phasor trajectory, a power angle trajectory and a frequency trajectory in a future preset time window; respectively carrying out corresponding evaluation and analysis, and outputting corresponding evaluation and analysis results; and respectively calculating an active power injection instruction in a power angle support mode, a reactive power injection instruction in a voltage phase correction mode or an anti-phase power injection instruction in an oscillation suppression mode according to an evaluation analysis result, and controlling the flywheel body to output power. According to the method, the power grid phasor trajectory is predicted, risks can be pre-judged and control measures can be actively taken before instability occurs, the defect of traditional afterward response is changed, passive is changed into active, and the timeliness and effectiveness of control are improved.

Systems and techniques are disclosed for improving real-time tissue characterizations during endovascular procedures. In some implementations, a method involves characterizing biological tissue for an endoluminal procedure. A first electrode is positioned within an endoluminal space adjacent to a region of biological tissue. A second electrode is positioned spatially separated from the first electrode. A variable-frequency input electrical signal is applied across the first electrode and the second electrode to generate an electrical field corresponding to the region. A voltage response is measured between the first electrode and the second electrode based on the electric field. A voltage phasor is determined based on the voltage response relative to the variable-frequency input electrical signal. A characteristic of the region is determined based on the voltage phasor.

This application relates to a method, system, and device for calculating the DC component of short-circuit current in a power system. The method includes obtaining the fault node in the power system network topology, the number M of branches connected to the fault node, the active voltage phasor of the fault point, and the branch current phasor of each branch connected to the fault node; calculating the equivalent impedance phasor and decay time constant corresponding to each branch based on the active voltage phasor and branch current phasor; obtaining the time after the fault, and calculating the DC component of the short-circuit current based on the time after the fault, the branch current phasor, and the decay time constant; and calculating the DC component of the short-circuit current to ground of the fault node for the M branches. This method calculates the DC component of the short-circuit current of each branch connected to the fault node separately, and incorporates the decay time constant of the branch during the calculation process, resulting in more accurate calculations of the DC component of the short-circuit current of the branches.

The present application relates to the technical field of electric power metering, and provides a voltage transformer error prediction model construction method, an error evaluation method and a device, the construction method comprising: collecting voltage and current phasors of a monitoring node and obtaining three-phase admittance parameters; constructing a node feature matrix based on the voltage and current phasors, establishing a graph adjacency matrix based on the three-phase admittance parameters, and using the node feature matrix and the graph adjacency matrix to perform error prediction by using a graph neural network to obtain voltage and current prediction errors; obtaining voltage estimated true values based on the voltage phasors and the voltage prediction errors, obtaining current estimated true values based on the current phasors and the current prediction errors, and determining voltage drop and current balance constraint losses of a three-phase transmission line based on the voltage estimated true values and the current estimated true values; and performing parameter iteration on the graph neural network based on the voltage drop and the current balance constraint losses to obtain an error prediction model. The method and device provided by the present application can maintain stable performance under different operating conditions and network topologies.

The invention relates to the technical field of power system operation and control, and discloses a pooling station monitoring data-based new energy base rapid frequency supporting capability monitoring method, which comprises the following steps of: firstly, automatically identifying a disturbance moment based on frequency and power change characteristics, and carrying out smoothing and exception suppression processing on disturbance data; then combining frequency response mechanisms of wind power, photovoltaic and energy storage equipment to construct an inertia response characteristic and primary frequency modulation characteristic model of the new energy base, and identifying an equivalent inertia constant and an equivalent droop coefficient of the base by using measurement data during disturbance; solving the external equivalent reactance of the new energy base based on the sensitivity relationship between the complex power and the voltage phasor; and finally, calculating the fast frequency support capacity, sustainable support duration and frequency response index of the new energy base in combination with the parameters, thereby realizing online monitoring and evaluation of the fast frequency support capacity.

The invention provides a new energy station mutual inductor signal adaptive decomposition method and system, and the method comprises the steps: collecting the voltage vector of each voltage transformer node in a transformer substation and a new energy station at the same time, constructing an observation data set based on the voltage vector of each voltage transformer node, and carrying out the preprocessing of the observation data set; and constructing a multi-target constraint based on variational mode decomposition, decomposing a voltage vector in the preprocessed observation data set through an NSGA-II algorithm under the multi-target constraint, and outputting each mode component in a voltage signal. According to the scheme, the accuracy and adaptability of mutual inductor signal decomposition can be improved, and the calculation cost in the decomposition process can be reduced.

The invention relates to the technical field of electric power measurement, and provides a voltage transformer error prediction model construction method and an error evaluation method and device, and the construction method comprises the steps: collecting the voltage and current phasors of a monitoring node, and obtaining a three-phase admittance parameter; constructing a node feature matrix based on the voltage and current phasors, establishing a graph adjacency matrix based on the three-phase admittance parameters, and performing error prediction by using the node feature matrix and the graph adjacency matrix and adopting a graph neural network to obtain voltage and current prediction errors; obtaining a voltage estimation truth value based on the voltage phasor and the voltage prediction error, obtaining a current estimation truth value based on the current phasor and the current prediction error, and determining voltage drop and current balance constraint loss of the three-phase power transmission line based on the voltage estimation truth value and the current estimation truth value; and performing parameter iteration on the graph neural network based on the voltage drop and the current balance constraint loss to obtain an error prediction model. According to the method and the device provided by the invention, the stable performance can be kept under different operation conditions and network topologies.

The invention discloses a complex valued neural network dynamic modeling method for power grid fault identification and prediction, and relates to the field of smart power grids. According to the method, a separated complex valued neural network is constructed, voltage phasors and power vectors in a complex number form are input, and power grid characteristics are extracted through not less than 3 complex number convolution layers and not less than 2 full connection layers. And training the model by using historical loop closing operation data not less than 100,000 times, wherein the training period does not exceed 4 hours. The model can accurately predict loop closing current amplitude and output voltage deviation, and a continuous prediction value is converted into a switch state decision signal through an embedded binarization module. According to the invention, the precision and efficiency of power grid loop closing operation and fault prediction are improved, and core model support is provided for intelligent operation and maintenance of the power grid.

The present disclosure relates to a fault detection method for a power transmission line (101) in an alternating current (AC) power transmission system (100). The method comprises: - obtaining local voltage phasors and local current phasors of a local position of the power transmission line; - obtaining transmission properties for the power transmission line from the local position to a remote position at a distance from the local position and for associated devices, wherein the transmission properties comprise series parameters, shunt parameters, and the distance from the local position to the remote position; - estimating, for the remote position, estimated remote voltage phasors and estimated remote current phasors on basis of the local voltage phasors, the local current phasors, and the transmission properties; - receiving, via a communication link (115), data relating to remote phase currents and determining measured remote current phasors; - determining whether a fault has occurred or not on basis of at least one of a combination of the estimated and measured remote current phasors and a combination of the estimated and measured remote voltage phasors; and - determining whether a fault is a true fault or a false fault, including: • comparing a first phase angle and a first magnitude of an estimated remote positive sequence current phasor with a second phase angle and a second magnitude of a measured remote positive sequence current phasor; • determining, on basis of the comparison, whether there is a significant channel asymmetry on the communication link; and • determining that the fault is a false fault if there is a significant channel asymmetry.

The invention discloses a power grid adaptive direction distance protection method and system based on an apparent power supply, and the method comprises the steps: building a home terminal dynamic equivalent apparent power supply model based on a voltage phasor and a current phasor obtained through measurement at a protection installation part, and enabling the model to be defined by two key parameters, namely, an apparent power supply voltage amplitude and equivalent impedance; three-phase voltage and three-phase current at a protection installation position are collected in real time, positive sequence voltage is calculated through a symmetrical component method, and the real-time phase difference between the dynamic equivalent apparent power source at the terminal and the three-phase voltage and the three-phase current is calculated; comparing the real-time phase difference with a preset action interval; when the real-time phase difference is in a set action interval, judging that a fault is a forward fault, and starting a protection action; and otherwise, a reverse fault is determined, and latching protection output is carried out. According to the method, the dependence of traditional protection on fixed source impedance parameters is effectively overcome, multiple control strategies such as unit power factor control, low voltage ride through and negative sequence current suppression of the wind turbine generator are adaptively compatible, and the interference of harmonic waves and power fluctuation on protection is remarkably suppressed.

The invention relates to a PMU-based power distribution network adaptive reclosing method, device and equipment and a medium, and the method comprises the steps: obtaining preprocessed multi-dimensional operation data through PMUs installed at the two sides of each circuit breaker of a power distribution network after the power distribution network breaks down; identifying a fault section of the multi-dimensional operation data, constructing a total vector difference sequence according to the voltage phasor difference between the fault section and the adjacent power frequency period, and generating a discrimination result based on the total vector difference sequence and the voltage amplitude change before and after the fault; performing stability and temperature rise evaluation on the multi-dimensional operation data corresponding to the judgment result to obtain the operation safety level of each fault section; determining a target section from the fault sections according to the judgment result and the operation safety level; and generating a fault coincidence decision based on a preset coincidence rule, and then reclosing the target section according to the fault coincidence decision. The method has the effect of improving the reclosing efficiency of the power distribution network in the fault line section.

The application provides a grid-connected friendly energy storage converter self-networking control protection method, device and medium. The method comprises the following steps: collecting electrical quantities of a grid-connected point and a direct current side, establishing a short-circuit capacity estimation value and a positive and negative zero sequence model, and generating a voltage phasor reference; generating a frequency given value and a voltage given value according to power and frequency droop and reactive power and voltage droop; performing generalized impedance shaping in a control loop, configuring virtual impedance and selective filtering according to frequency bands; completing grid connection or reconnection according to the order of frequency slope, phase angle alignment and voltage amplitude convergence based on the grid-connected point reference phasor; setting positive sequence, negative sequence and zero sequence fault current upper limits and time sequence templates in a symmetrical component domain; and outputting the frequency given value, the voltage given value, the sequence component limit value and the protection state instruction to a converter power bridge drive and a grid-connected switch control interface. The application can realize no-phase-lock grid connection synchronization, unified control protection switching, sequence component controlled fault current and weak grid stable operation.

This invention discloses a method, system, equipment, and medium for panoramic identification of short-circuit parameters in distribution networks based on multi-frequency disturbance excitation. It belongs to the field of power system condition monitoring and fault analysis technology. The method includes: designing and generating a composite disturbance signal; injecting the composite disturbance signal into the bus under test of the distribution network through a controllable current source, and acquiring time-domain waveform data of the injected current signal and the bus voltage; performing frequency domain transformation to separate and extract voltage and current phasors in the frequency domain; obtaining short-circuit impedance measurements at each frequency point using a first algorithm; and identifying equivalent circuit parameters using the short-circuit impedance measurements at several characteristic frequency points through a parameter fitting method. Compared to traditional single-frequency measurements that can only acquire single-point data, this method provides more comprehensive panoramic parameter information, accurately reflecting the impedance characteristics of the distribution network at different frequencies, and is suitable for modern distribution networks containing a large number of nonlinear loads and power electronic equipment.

The application discloses a bus low capacitance resistance protection method and system based on bus equivalent parameters, and comprises the following steps: acquiring three-phase voltage phasor values of a bus and three-phase current phasor values of each branch in the bus; determining three-phase bus differential currents based on the three-phase current phasor values of each branch in the bus; correcting the three-phase voltage phasor values of the bus to obtain three-phase voltage correction values; determining corresponding bus-to-ground capacitances of each phase based on the three-phase bus differential currents and the three-phase voltage correction values; and performing protection on any phase based on the corresponding bus-to-ground capacitance of the any phase and the three-phase bus differential current according to a preset protection criterion. The application identifies bus faults by the significant reduction of the bus-to-ground capacitance equivalent parameter when a fault occurs in the bus area. Since the bus-to-ground capacitance is a bus equivalent parameter, the system operation mode has no influence on the bus-to-ground capacitance, so that the protection reliability can be ensured, the sensitivity of the differential protection can be greatly improved, and the safe and stable operation level of the system is improved.

This invention discloses a method, apparatus, electronic device, and storage medium for determining node voltages in an electromechanical transient network containing an infinite bus, belonging to the field of power system electromechanical transient simulation technology. The method includes: obtaining the node admittance matrix of the power system to be simulated and the injected current of each grid-connected device except the infinite bus; solving the equivalent impedance matrix based on the node admittance matrix to obtain the self-impedance of the infinite bus and its mutual impedance with each node; calculating the total equivalent voltage drop formed at the infinite bus by each grid-connected device in conjunction with its injected current and corresponding mutual impedance; deriving the injected current of the infinite bus based on the infinite bus voltage phasor, self-impedance, and total voltage drop; and substituting the injected current of the infinite bus and the injected currents of other grid-connected devices into the node admittance matrix to solve the network equations to obtain the voltages of each node. The implementation of this invention can solve the problem of network node voltages deviating from preset standards during transient processes in existing technologies.

This application provides a method for determining the distance to a fault in a hybrid line system. The method may include: calculating a first set of voltage phasors and current phasors based on at least a portion of measured voltage samples and measured current samples; calculating ABCD parameters associated with the hybrid line system based on at least a portion of input line parameters; calculating a second set of voltage phasors and current phasors based on at least a portion of the first set of voltage phasors, current phasors and ABCD parameters; collecting fault phase voltage phasors and current phasors based on at least a portion of the second set of voltage phasors and current phasors; identifying faults and associated parameters in the fault section of the hybrid line system based on at least a portion of the fault phase voltage phasors and current phasors; and calculating the distance to the fault based on at least a portion of the associated parameters.

The invention discloses a double-bus multi-incoming-line intelligent spare power automatic switching and self-recovery cooperative control method, and belongs to the technical field of power system automation. Aiming at the problems of extensive spare power automatic switching and self-recovery control and lack of intelligent parallel judgment and dynamic load regulation capability in a double-bus multi-inlet-wire power supply system, a multi-level priority decision-making mechanism is constructed, and switching priorities are set for inlet wires and bus couplings, so that orderly switching and recovery of a power supply are realized; incoming line voltage phasor information is collected in real time, an amplitude value, a phase angle and a frequency difference threshold value are set, intelligent paralleling condition judgment is achieved, and non-synchronous closing is avoided; and dynamically monitoring and adjusting load distribution based on the maximum load value of the incoming line and the load priority coefficient of the feeder line, preventing overload and optimizing the operation mode. The power supply reliability, the system stability and the load adaptability are improved, and the method is suitable for intelligent operation control of important load centers such as substations.

The invention discloses a photovoltaic inverter power regulation method and device based on distributed photovoltaic power generation. The method comprises the steps that electric power data of a target power distribution network at the current moment are collected, and the electric power data comprise the voltage amplitude of a target node in the target power distribution network; determining a voltage regulation redundancy value of the target node at the current moment based on the voltage amplitude; if the voltage regulation redundancy value is greater than a preset threshold value, determining a target instantaneous voltage phasor histogram entropy of the target node at the current moment and a target source load correlation sensitivity coefficient; determining the target reactive power of the photovoltaic inverter in the target power distribution network at the current moment based on the target instantaneous voltage phasor direct square entropy and the target source load correlation sensitivity coefficient; and performing power regulation on the photovoltaic inverter according to the target reactive power. According to the invention, the technical problem that the power regulation effect of a photovoltaic inverter based on distributed photovoltaic power generation is not ideal in the prior art is solved.

The present application relates to a kind of power distribution network three-phase imbalance governance scheduling method, equipment and medium, belong to power control technical field, including the following steps: obtaining the three-phase voltage phasor and load current phasor of each node of power distribution network, calculate node and system voltage imbalance degree;Construct the branch estimation impedance matrix of power distribution network and obtain active power loss;With each node voltage imbalance degree training graph neural network, learn the propagation strength of voltage imbalance degree between nodes, get propagation matrix;Anti-causal analysis is carried out to propagation matrix, and the imbalance source contribution degree vector is obtained;Comprehensive power distribution network voltage imbalance degree, active power loss, contribution degree vector and current phasor, decision three-phase compensation current effective value vector, realize each node three-phase imbalance governance.The present application constructs complete power grid state using whole network electrical quantity, makes scheduling overall node electrical coupling relationship.

A method for regulating a grid-coupled power converter includes adjusting a control voltage for the power converter in dependence on an output voltage of the power converter. The method provides limiting a voltage deviation between the control voltage and the output voltage. In embodiments, the limitation of a control voltage phasor takes place in amplitude and angle, wherein control ranges for amplitude and / or angle are adjusted depending on the situation. In further embodiments, the limitation takes place in coordinates of coordinate axes that are orthogonal and rectilinear to each other. Further, in a method for regulating a power converter, when determining a control quantity, a potential difference between a reference potential of the output voltage and a reference potential of a bridge voltage of the power converter is considered. Alternatively or additionally, contribution of a voltage oscillation in an intermediate circuit to the bridge voltage is considered.

The application provides a power distribution network two-stage fault locating method and device based on synchronous phasor measurement, comprising the following steps: acquiring network topology before fault, voltage phasor measurement data before and after fault and three-phase active and reactive power injection pseudo measurement of all unbalanced nodes; constructing a virtual current fault locating model, enumerating each possible fault line, solving the fault locating model, obtaining a first matching index value, sorting all first matching index values in ascending order, selecting the first u lines to construct a candidate fault line set; performing nonlinear fault state estimation (SE) on all associated nodes of the candidate fault line in sequence, selecting the node with the highest matching degree as the fault line endpoint, and obtaining one endpoint of the fault line; and determining the fault line and the accurate fault position by using other hardware-based methods; the application can realize high fault locating accuracy under the condition of limited muPMU.

The application relates to the technical field of electric power, and provides a main distribution coordination combined loop power supply strategy optimization method and system, which comprises the following steps: dividing a target distribution network into a plurality of topological regions, and obtaining a main distribution topological coupling relationship according to the connection relationship between each topological region and a main network power supply node; obtaining a loop current dominant component type of each loop path to be combined between regions according to obtained first and second voltage phasors of a first topological region and a second topological region to be combined; generating a candidate paired path set based on the criterion that different loop current dominant component types are allowed to be paired; and performing paired path loop current vector offset effect analysis on the candidate paired path set according to a to-be-combined path constraint transfer relationship matrix determined based on the main distribution topological coupling relationship, so as to obtain a target combined loop power supply strategy. The application can improve the effectiveness of combined loop power supply strategy generation and guarantee the safety and reliability of combined loop power supply operation.

The application discloses a substation main transformer high-voltage side harmonic voltage measurement accuracy discrimination method and system, and the method comprises the following steps: synchronously collecting harmonic voltage phasors of a substation main transformer high-voltage side, medium-voltage side and low-voltage side power supply bus and harmonic current phasors of each outgoing line within the same time; establishing an equivalent impedance model of the main transformer high-voltage side, medium-voltage side and low-voltage side according to main transformer specification parameters; calculating the neutral point harmonic voltage of the main transformer equivalent impedance model; calculating the main transformer medium-voltage side harmonic voltage, comparing the main transformer medium-voltage side harmonic voltage with the actually measured main transformer medium-voltage side harmonic voltage, discriminating the main transformer medium-voltage side harmonic voltage measurement accuracy, calculating the main transformer high-voltage side harmonic voltage, comparing the main transformer high-voltage side harmonic voltage with the actually measured main transformer high-voltage side harmonic voltage, and discriminating the main transformer high-voltage side harmonic voltage measurement accuracy. The application solves the technical problem of discriminating whether the substation main transformer high-voltage side and medium-voltage side exist harmonic voltage measurement distortion.