Power system voltage control method and device based on dynamic steady-state collaborative correction

Abstract

This invention provides a power system voltage control method and apparatus based on dynamic steady-state collaborative correction. The method includes: establishing an electromagnetic transient model for a preset voltage node in the electromagnetic transient simulation software PSCAD; simplifying the power grid with an electrical distance to the target area exceeding a preset distance into a dynamic Thevenin equivalent model; initializing power flow calculations in the Power System Phasor Measurement Unit (BPA) to obtain a dynamic-steady-state hybrid model; updating the dynamic Thevenin equivalent parameters of the power system in real time based on power system phasor measurement unit data and synchronizing them to the BPA; based on the dynamic-steady-state hybrid model, suppressing transient overvoltages in the power system within a time period less than a first preset time period; and optimizing the steady-state voltage of the power system within a time period less than a second preset time period by combining wide-area coordinated control, thereby achieving bidirectional correction of parameters between the dynamic and steady-state models, reducing the prediction error of the head-end voltage, and improving the robustness of voltage control.

Description

Technical Field

[0001] This invention relates to the field of power system simulation and control technology, and in particular to a power system voltage control method and device based on dynamic steady-state collaborative correction. Background Technology

[0002] With the rapid development of modern power systems, ultra-high voltage (UHV) and extra-high voltage (UHV) transmission technologies are widely used due to their ability to achieve large-capacity, long-distance power transmission. However, UHV lines may experience load shedding during operation, which can significantly affect the steady-state voltage of the lines. Load shedding refers to the sudden disappearance of load on the transmission line due to fault clearing or a sudden reduction in load. When UHV lines experience load shedding, the line's capacitive effect causes the line voltage to rise rapidly, potentially exceeding the insulation withstand level of the equipment, thereby damaging the equipment. In severe cases, it can even trigger system voltage instability, leading to large-scale power outages. Therefore, accurately predicting and controlling the voltage change trend at the line's starting end after load shedding is crucial for ensuring the safe and stable operation of the power system.

[0003] Currently, the commonly used methods for controlling the voltage at the head-end bus of a power line are mainly linear calculation and power flow calculation. The linear calculation method uses Power Systems Computer Aided Design (PSCAD) software to perform Thevenin equivalent modeling of the power grid, determining the head-end voltage control value by calculating the voltage difference before and after a trip. The power flow calculation method relies on power flow simulation using Berkeley Power Analysis (BPA) software, adjusting reactive power compensation equipment to verify the head-end voltage. However, both methods have several problems in voltage prediction calculation. For example, there is a disconnect between dynamic and steady-state models; the Thevenin equivalent model ignores the dynamic response of generator excitation regulation and reactive power compensation equipment, leading to an underestimation of the head-end voltage under heavy load; and BPA power flow calculation relies on steady-state assumptions, potentially overestimating the system's reactive power regulation capability and failing to capture transient overvoltage risks. Summary of the Invention

[0004] This invention provides a power system voltage control method and apparatus based on dynamic steady-state collaborative correction, which solves the technical problem of low voltage control accuracy in power systems in the prior art.

[0005] On the one hand, the present invention provides a power system voltage control method based on dynamic steady-state collaborative correction, comprising:

[0006] In the power system electromagnetic transient simulation software PSCAD, an electromagnetic transient model is established for the preset voltage nodes. The power grid with an electrical distance to the target area exceeding the preset distance is simplified into a dynamic Thevenin equivalent model. Power flow calculation is initialized in BPA, generators are set as PV nodes and loads are set as PQ nodes. The parameters of reactive power compensation equipment are configured to obtain a dynamic-steady-state hybrid model.

[0007] The dynamic Thevenin equivalent parameters of the power system are updated in real time based on the data from the power system phasor measurement unit and synchronized to the BPA;

[0008] Based on the dynamic-steady-state hybrid model, transient overvoltages in the power system are suppressed within a time period less than the first preset time period, and the steady-state voltage of the power system is optimized within a time period less than the second preset time period by combining wide-area coordinated control.

[0009] Based on a dynamic-steady-state hybrid model, the control effect of the power system is verified, and the control strategy is adaptively adjusted according to the actual situation of the power system.

[0010] According to the present invention, a power system voltage control method based on dynamic steady-state collaborative correction is provided. An electromagnetic transient model is established for a preset voltage node in the power system electromagnetic transient simulation software PSCAD. The power grid whose electrical distance to the target area exceeds a preset distance is simplified into a dynamic Thevenin equivalent model, including:

[0011] Calculate the voltage sensitivity of each voltage node in the power system to power changes, and analyze the topology of the power system. Based on the sensitivity and topology, the preset voltage nodes are obtained.

[0012] Configure the model parameters of the electromagnetic transient model based on the parameter file of BPA to keep the model parameters consistent with the steady-state data of BPA;

[0013] For power grids whose electrical distance to the target area exceeds a preset distance, the equivalent impedance and equivalent voltage source are calculated using the short-circuit capacity method or the N-1 fault scanning method to obtain a dynamic Thevenin equivalent model.

[0014] According to the present invention, a power system voltage control method based on dynamic steady-state collaborative correction calculates the voltage sensitivity of each voltage node in the power system to power changes and analyzes the topology of the power system. Based on the sensitivity and topology, a preset voltage node is obtained, including:

[0015] Calculate the ratio of voltage to corresponding power at each voltage node in the power system, as the sensitivity.

[0016] Sort the sensitivities from smallest to largest;

[0017] According to the sorting, select a preset number of voltage nodes corresponding to the sensitivity, as well as voltage nodes located in the backbone network, new energy aggregation point and load center in the topology as preset voltage nodes.

[0018] According to the present invention, a power system voltage control method based on dynamic steady-state collaborative correction is provided, which calculates the equivalent impedance using the short-circuit capacity method, including:

[0019] Based on the power flow calculation results, the short-circuit capacity is obtained;

[0020] Calculate the ratio of the square of the grid connection point voltage to the short-circuit capacity, and use it as the equivalent impedance;

[0021] The equivalent impedance is calculated using the N-1 fault scan method, including:

[0022] Simulate a three-phase short-circuit fault at a preset node in PSCAD to obtain the fault current;

[0023] Calculate the ratio of the voltage before the fault to the fault current, and use it as the equivalent impedance.

[0024] According to the present invention, a power system voltage control method based on dynamic steady-state collaborative correction updates the dynamic Thevenin equivalent parameters of the power system in real time based on the power system phasor measurement unit data and synchronizes them to the BPA, including:

[0025] Samples are taken from preset nodes in the power system to obtain voltage and current sampling data;

[0026] Preprocess the sampled data;

[0027] Based on the preprocessed sampling data, the dynamic Thevenin equivalent parameters are updated in real time using the sensitivity method.

[0028] The updated dynamic Thevenin equivalent parameters are synchronized to BPA via the data interface.

[0029] According to the present invention, a power system voltage control method based on dynamic steady-state collaborative correction utilizes a sensitivity method to update dynamic Thevenin equivalent parameters in real time, including:

[0030] The sensitivity method is used to compare the voltage and current changes in the current cycle with those in the previous cycle.

[0031] Determine the ratio of voltage change to current change as the impedance change;

[0032] The updated equivalent impedance is obtained based on the impedance change, the smoothing coefficient of the impedance change, and the equivalent impedance of the previous period.

[0033] The updated voltage value is obtained based on the updated equivalent impedance and the current and voltage values ​​of the current cycle.

[0034] According to the power system voltage control method based on dynamic steady-state collaborative correction provided by the present invention, the impedance change is expressed by the following formula:

[0035] ;

[0036] in, The change in impedance. This is the voltage value from the previous cycle. The current value is from the previous cycle, and k represents the cycle. This is the voltage value for the current cycle. This represents the current value for the current cycle.

[0037] The updated equivalent impedance is expressed by the following formula:

[0038] ;

[0039] For the updated equivalent impedance, This is the equivalent impedance of the previous cycle. This is the smoothing coefficient.

[0040] According to the present invention, a power system voltage control method based on dynamic steady-state collaborative correction synchronizes the updated dynamic Thevenin equivalent parameters to the BPA via a data interface, including:

[0041] The updated dynamic Thevenin equivalent parameters are synchronized to BPA by calling the BPA interface through a Python script;

[0042] If the rate of change of parameter impedance and the phase change of voltage source reach the set threshold after BPA update, then power flow recalculation is performed.

[0043] Read the generator voltage setting and reactive power compensation command output by BPA and send them back to PSCAD.

[0044] According to the present invention, a power system voltage control method based on dynamic steady-state collaborative correction suppresses transient overvoltages in the power system for a period of less than a first preset time, comprising:

[0045] When a transient overvoltage peak is detected to exceed the first preset voltage threshold or the voltage change rate exceeds the preset change threshold, the reactive power output is calculated based on the preset proportional gain, integral gain and reserved safety margin in order to quickly respond to and suppress the transient overvoltage.

[0046] When the steady-state voltage deviation exceeds the second preset voltage threshold and the duration exceeds the first preset duration threshold, the step size is adjusted according to a preset ratio. If the number of adjustments reaches the preset number within the preset time period, the blocking condition is activated.

[0047] Optimizing the steady-state voltage of the power system within a time period less than a second preset duration by combining wide-area coordinated control includes:

[0048] Calculate the reactive power sensitivity of each generator to the head-end voltage, select the two units with the highest sensitivity, and adjust the excitation voltage command according to the voltage deviation and the preset automatic voltage regulator proportional gain.

[0049] When the voltage is lower than the third preset voltage threshold for a duration exceeding the second preset duration, and all reactive power resources have been exhausted, load shedding is performed according to priority and gradient.

[0050] On the other hand, the present invention also provides a power system voltage control device based on dynamic steady-state cooperative correction, comprising:

[0051] The dynamic steady-state module is used to establish electromagnetic transient models for preset voltage nodes in the power system electromagnetic transient simulation software PSCAD, simplify the power grid with an electrical distance to the target area that exceeds the preset distance into a dynamic Thevenin equivalent model, initialize power flow calculation in BPA, set generators as PV nodes and loads as PQ nodes, configure reactive power compensation equipment parameters, and obtain a dynamic-steady-state hybrid model.

[0052] The parameter update module is used to update the dynamic Thevenin equivalent parameters of the power system in real time based on the data from the power system phasor measurement unit and synchronize them to the BPA.

[0053] The voltage graded control module is used to suppress transient overvoltages in the power system within a time period of less than a first preset time period based on a dynamic-steady-state hybrid model, and to optimize the steady-state voltage of the power system within a time period of less than a second preset time period in combination with wide-area coordinated control.

[0054] The verification module is used to verify the control effect of the power system based on the dynamic-steady-state hybrid model, and to adaptively adjust the control strategy according to the actual situation of the power system.

[0055] The present invention provides a power system voltage control method and apparatus based on dynamic steady-state collaborative correction. In the power system electromagnetic transient simulation software PSCAD, an electromagnetic transient model is established for a preset voltage node. Power grids with electrical distances exceeding a preset distance to the target area are simplified into dynamic Thevenin equivalent models. Power flow calculations are initialized in the Power System Phasor Measurement Unit (BPA) to obtain a dynamic-steady-state hybrid model. The dynamic Thevenin equivalent parameters of the power system are updated in real time based on power system phasor measurement unit data and synchronized to the BPA. Based on the dynamic-steady-state hybrid model, transient overvoltages in the power system are suppressed within a time period less than a first preset time. Combined with wide-area coordinated control, the steady-state voltage of the power system is optimized within a time period less than a second preset time. Through dynamic Thevenin parameter updates and a hybrid simulation framework, bidirectional parameter correction between the dynamic (PSCAD) and steady-state (BPA) models is achieved, reducing the first-end voltage prediction error. Combined with transient overvoltage suppression and steady-state reactive power optimization, the robustness of voltage control is improved, supporting scenarios with a high proportion of renewable energy integration. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0057] Figure 1 This is a flowchart illustrating the power system voltage control method based on dynamic steady-state collaborative correction provided in an embodiment of the present invention.

[0058] Figure 2 This is a schematic diagram of the power system grid provided in an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of the structure of a power system voltage control device based on dynamic steady-state collaborative correction provided in an embodiment of the present invention;

[0060] Figure 4 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0062] Figure 1This is a schematic flowchart of a power system voltage control method based on dynamic steady-state collaborative correction provided in an embodiment of the present invention.

[0063] See Figure 1 The power system voltage control method based on dynamic steady-state collaborative correction may include the following steps 101 to 104.

[0064] Step 101: In the power system electromagnetic transient simulation software PSCAD, establish an electromagnetic transient model for the preset voltage nodes, simplify the power grid with an electrical distance to the target area that exceeds the preset distance into a dynamic Thevenin equivalent model, initialize the power flow calculation in BPA, set the generator as a PV node and the load as a PQ node, configure the reactive power compensation equipment parameters, and obtain a dynamic-steady-state hybrid model.

[0065] In this step, during power system flow calculations, PV nodes refer to nodes with given voltage amplitude and active power, typically representing generator nodes. PQ nodes refer to nodes with given active and reactive power, typically representing load nodes. Power grids with an electrical distance exceeding a preset distance to the target area can also be called remote power grids. Preset voltage nodes generally refer to end-point generators and renewable energy power plants. While establishing electromagnetic transient models for preset voltage nodes, dynamic characteristics can be preserved, such as excitation regulation and wind turbine control. Reactive power compensation equipment parameters can refer to reactive power output range, response speed, and control mode. The parameter configuration of the electromagnetic transient model can be consistent with the data in the corresponding BPA and can be configured according to the parameter file in the BPA.

[0066] When configuring BPA, initial Thevenin parameters (such as initial Thevenin equivalent voltage and initial Thevenin equivalent impedance) can be exported from PSCAD, and the BPA card can be formatted. The generator is set as a PV node (voltage control mode), and the SVC / SVG is set as a PQ node (adjustable reactive power output). The transformer tap adjustment step size (e.g., ±1.25%) is defined. Data (Thevenin equivalent voltage and voltage source parameters) is transmitted in real time via the PMU to generate dynamically updated parameters (Thevenin equivalent voltage and voltage source parameters). The initial generator power flow matching with the power flow can be verified in the dynamic layer to avoid simulation divergence; BPA power flow iterations are performed in the static layer to ensure consistency between the Thevenin equivalent voltage and the system power balance. Before the first power flow calculation, at least three iterations must be performed in BPA to ensure that the Thevenin equivalent voltage matches the generator setpoint.

[0067] In the power system electromagnetic transient simulation software PSCAD, an electromagnetic transient model is established for a preset voltage node. Power grids with electrical distances exceeding a preset distance to the target area are simplified into dynamic Thevenin equivalent models, which may include:

[0068] Calculate the sensitivity of voltage nodes in a power system to changes in power (such as active and reactive power), and analyze the topology of the power system. Based on the sensitivity and topology, the preset voltage nodes are obtained.

[0069] Configure the model parameters of the electromagnetic transient model based on the parameter file of BPA to keep the model parameters consistent with the steady-state data of BPA;

[0070] For power grids whose electrical distance to the target area exceeds a preset distance, the equivalent impedance and equivalent voltage source are calculated using the short-circuit capacity method or the N-1 fault scanning method to obtain a dynamic Thevenin equivalent model.

[0071] Calculate the voltage sensitivity of each voltage node in a power system to power changes, and analyze the power system topology. Based on the sensitivity and topology, determine the preset voltage nodes, which may include:

[0072] Calculate the ratio of voltage to corresponding power at each voltage node in the power system, as the sensitivity.

[0073] Sort the sensitivities from smallest to largest;

[0074] According to the sorting, select a preset number of voltage nodes corresponding to the sensitivity, as well as voltage nodes located in the backbone network, new energy aggregation points and load centers in the topology (such as 500kV hub stations and wind farm grid connection points) as preset voltage nodes.

[0075] The preset quantity can be set, for example, to the top 10%. The backbone network is the core of the power system, responsible for transmitting electricity from power plants to various load centers and substations. The backbone network typically consists of high-voltage transmission lines. A renewable energy aggregation point refers to a node that aggregates electricity from multiple renewable energy power plants (such as wind farms and photovoltaic power plants) and transmits the electricity to the backbone grid through that node. A load center refers to an area or node in the power system with high electricity demand, typically a city center, industrial area, or large commercial area.

[0076] The equivalent impedance is calculated using the short-circuit capacity method, including:

[0077] Based on the power flow calculation results, the short-circuit capacity is obtained;

[0078] Calculate the ratio of the square of the grid connection point voltage to the short-circuit capacity, and use it as the equivalent impedance. Specifically, use the following formula (1):

[0079] (1);

[0080] in, For the system's short-circuit capacity, The voltage at the grid connection point. It is the equivalent impedance.

[0081] The equivalent impedance is calculated using the N-1 fault scan method, including:

[0082] Simulate a three-phase short-circuit fault at a preset node (such as the point of common coupling) in PSCAD to obtain the fault current;

[0083] Calculate the ratio of the voltage before the fault to the fault current, and use it as the equivalent impedance. Specifically, see formula (2) below:

[0084] (2);

[0085] in, For fault current, This is the voltage before the fault.

[0086] The calculation method for the equivalent voltage source is shown in the following formula (3):

[0087] (3);

[0088] in, As the reference current, It is an equivalent voltage source. The reference current is calculated as shown in formula (4):

[0089] (4);

[0090] in, As the reference power, This is the reference voltage.

[0091] Step 102: Update the dynamic Thevenin equivalent parameters of the power system in real time based on the data from the power system phasor measurement unit, and synchronize them to the BPA.

[0092] Step 102 may specifically include:

[0093] Samples are taken from preset nodes in the power system to obtain voltage and current sampling data;

[0094] Preprocess the sampled data;

[0095] Based on the preprocessed sampling data, the dynamic Thevenin equivalent parameters are updated in real time using the sensitivity method.

[0096] The updated dynamic Thevenin equivalent parameters are synchronized to BPA via the data interface.

[0097] The general principle for the placement of phasor measurement units (PMUs) is as follows:

[0098] Key monitoring points (preset nodes): the first bus (control voltage node), the grid connection point of new energy power plants, and both ends of the main transmission line.

[0099] Redundancy configuration: Key nodes are configured with dual PMUs (master and backup mode), with a sampling rate ≥ 4kHz and time synchronization accuracy ≤ 1μs (based on IEEE 1588 protocol).

[0100] Preprocessing mainly includes data filtering and outlier handling. Data filtering specifically includes:

[0101] FIR low-pass filter: cutoff frequency 100Hz, eliminates high-frequency noise (such as switching harmonics).

[0102] Recursive averaging filter: 10ms window width (40 sampling points) to smooth transient disturbances.

[0103] Abnormal data processing can mainly include:

[0104] If the voltage change rate is greater than 10kV, mark it as fault data and switch to the backup PMU;

[0105] If data is continuously lost for more than 5ms, linear interpolation compensation will be enabled.

[0106] Step 103: Based on the dynamic-steady-state hybrid model, suppress transient overvoltages in the power system within a time period less than the first preset time period, and combine wide-area coordinated control to optimize the steady-state voltage of the power system within a time period less than the second preset time period.

[0107] Step 104: Based on the dynamic-steady-state hybrid model, verify the power system control effect and adaptively adjust the control strategy according to the actual situation of the power system.

[0108] In this embodiment, an electromagnetic transient model is established for a preset voltage node in the power system electromagnetic transient simulation software PSCAD. The power grid with an electrical distance to the target area exceeding a preset distance is simplified into a dynamic Thevenin equivalent model, and power flow calculation is initialized in BPA to obtain a dynamic-steady-state hybrid model. The dynamic Thevenin equivalent parameters of the power system are updated in real time according to the power system phasor measurement unit data and synchronized to BPA. Based on the dynamic-steady-state hybrid model, transient overvoltages of the power system are suppressed within a time period less than a first preset time period, and the steady-state voltage of the power system is optimized within a time period less than a second preset time period in combination with wide-area coordinated control. Through dynamic Thevenin parameter update and hybrid simulation framework, bidirectional correction of parameters of the dynamic (PSCAD) and steady-state (BPA) models is realized, which reduces the prediction error of the first-end voltage. Combined with transient overvoltage suppression and steady-state reactive power optimization, the robustness of voltage control is improved, supporting high-proportion renewable energy access scenarios.

[0109] In one embodiment of this specification, the dynamic Thevenin equivalent parameter is updated in real time using the sensitivity method, including:

[0110] The sensitivity method is used to compare the voltage and current changes in the current cycle with those in the previous cycle.

[0111] Determine the ratio of voltage change to current change as the impedance change;

[0112] The updated equivalent impedance is obtained based on the impedance change, the smoothing coefficient of the impedance change, and the equivalent impedance of the previous period.

[0113] The updated voltage value is obtained based on the updated equivalent impedance and the current and voltage values ​​of the current cycle.

[0114] In this embodiment, the impedance change is determined by comparing the voltage and current changes in the current cycle with those in the previous cycle, thereby updating the equivalent impedance and voltage values ​​more accurately. Based on the impedance change and the smoothing coefficient, the equivalent impedance is dynamically adjusted so that the system can adapt to real-time changes in the power system.

[0115] In one embodiment of this specification, the impedance change is expressed by the following formula (5):

[0116] (5);

[0117] in, The change in impedance. This is the voltage value from the previous cycle. The current value is from the previous cycle, and k represents the cycle. This is the voltage value for the current cycle. This represents the current value for the current cycle.

[0118] The updated equivalent impedance is expressed by the following formula (6):

[0119] (6);

[0120] in, For the updated equivalent impedance, This is the equivalent impedance of the previous cycle. This is the smoothing coefficient.

[0121] In addition, the updated voltage source can be represented as As shown in the following formula (7):

[0122] (7).

[0123] In this embodiment, typically in high-noise scenarios (such as near wind farms), The value is 0.2, which is suitable for stable scenarios. The value is set to 0.5. By providing specific mathematical formulas to calculate impedance changes and update equivalent impedances, accurate updates to the dynamic Thevenin equivalent parameters of the power system can be achieved. This improves the accuracy of the power system model, making it more closely reflect actual operating conditions, and thus enhancing the reliability and effectiveness of power system voltage control.

[0124] In one embodiment of this specification, the updated dynamic Thevenin equivalent parameters are synchronized to the BPA via a data interface, including:

[0125] The updated dynamic Thevenin equivalent parameters are synchronized to BPA by calling the BPA interface through a Python script;

[0126] If the rate of change of parameter impedance and the phase change of voltage source reach the set threshold after BPA update, then power flow recalculation is performed.

[0127] Read the generator voltage setting and reactive power compensation command output by BPA and send them back to PSCAD.

[0128] In this embodiment, real-time synchronization between the dynamic Thevenin equivalent parameters of the power system and the BPA software is achieved through an automated data interface. This ensures the consistency between power system simulation and actual operating data, helps improve the accuracy of power flow calculation, and thus optimizes the voltage control and overall performance of the power system. The updated dynamic Thevenin equivalent parameters are synchronized to the BPA. For example, for Thevenin bus voltage, the VM (equivalent voltage source) field in the .dat file is directly modified; for equivalent line parameters, the R field (equivalent line resistance value) and the X field (equivalent line reactance value) are updated.

[0129] If the impedance change rate and voltage source phase change parameters reach the set thresholds after the BPA update, a power flow recalculation is performed. For example, the threshold for the impedance change rate can be 5%, and the threshold for the voltage source phase change can be 2 degrees. Power flow recalculation generally includes active power iterative calculation (such as...). Reactive power iterative calculation ( ) and convergence judgment ( processes such as pu. This is the change in active power. The admittance matrix of the power system. This represents the change in the phase angle of the node voltage. Let e ​​be the change in reactive power, and e be the base of the natural logarithm.

[0130] In this embodiment, after being sent back to PSCAD, a closed-loop verification and fault tolerance mechanism can also be executed so that multiple verification and rollback strategies can ensure system reliability in extreme scenarios.

[0131] The verification rules are as follows:

[0132] Dynamic layer verification: If the absolute value of the difference between the updated Thevenin equivalent voltage source and the voltage source of the previous cycle is greater than the specified threshold (such as 0.05 per unit (pu)), it is determined to be a parameter abnormality. In the case of parameter abnormality, the system will trigger the historical data rollback mechanism to restore to the previous state to ensure the stability of the system.

[0133] Steady-state layer verification: If the BPA power flow iteration count is greater than 50 and convergence is still not achieved, it is determined to be a model mismatch, and the system is switched to full dynamic simulation mode.

[0134] The fault tolerance strategy is as follows:

[0135] Data rollback: Retains the parameter history of the most recent 10 periods, and automatically rolls back to the most recent valid state in case of an anomaly;

[0136] Model downgrade: If the verification fails 3 times in a row, the parameter update function will be turned off, the Thevenin parameters will be fixed and an alarm will be issued.

[0137] In one embodiment of this specification, suppressing transient overvoltages in the power system within a time period shorter than a first preset duration (e.g., 10 ms) includes:

[0138] When a transient overvoltage peak is detected (which can be expressed as...) The voltage exceeds the first preset threshold voltage (which can be expressed as...). ) or the rate of voltage change exceeds a preset threshold (e.g. When the reactive power output is calculated based on the preset proportional gain, integral gain, and reserved safety margin, it can quickly respond to and suppress transient overvoltages. The calculation process of reactive power output is shown in the following formula (8):

[0139] (8);

[0140] in, To exert effort for no reason For proportional gain, For integral gain, To allow for a safety margin, t represents time. Reference voltage;

[0141] When the steady-state voltage deviation exceeds the second preset voltage threshold (e.g.) If the duration exceeds the first preset duration threshold (e.g., 30s), the step size is adjusted according to a preset ratio (e.g., ±1.25% (±6.25kV for 500kV systems)). If the number of adjustments reaches the preset number (e.g., 3 times) within a preset time period (e.g., 10 minutes), the interlocking condition is activated (the action is paused and an alarm is triggered).

[0142] Optimizing the steady-state voltage of the power system within a time frame less than a second preset duration (e.g., 100 ms) by combining wide-area coordinated control (generator excitation adjustment, load shedding) includes:

[0143] Calculate the reactive power sensitivity of each generator to the head-end voltage, select the two units with the highest sensitivity, and adjust the excitation voltage command according to the voltage deviation and the preset proportional gain of the automatic voltage regulator; specifically, the excitation voltage command can be shown in the following formula (9):

[0144] (9);

[0145] in, The new excitation voltage command controls the DC voltage output by the generator excitation system. This is the current excitation voltage value, reflecting the real-time status of the generator excitation system. This is the voltage deviation, typically the difference between the measured voltage and the reference voltage. The proportional gain of the automatic voltage regulator determines the excitation response speed and sensitivity, and is generally taken as 0.1 to 0.3 pu / kV.

[0146] When the voltage is lower than the third preset voltage threshold (e.g., 0.9 pu) for a duration exceeding the second preset duration (e.g., 5 seconds) and all reactive power resources have been exhausted, the load is switched off according to priority and gradient.

[0147] In this embodiment, the second preset duration is longer than the first preset duration. Priority settings generally follow the principle of prioritizing non-critical loads (such as commercial electricity) over industrial loads. Gradient settings generally follow the principle of cutting off 5% of the total load each time, with an interval of 10 seconds. By employing a strategy of suppressing transient overvoltages and optimizing steady-state voltage within different preset durations, and by rapidly responding to transient overvoltages combined with wide-area coordinated control to optimize steady-state voltage, the voltage stability and control accuracy of the power system can be effectively improved, thereby enhancing the system's reliability and security. The above thresholds can be set according to actual conditions, and no specific limitations are imposed here.

[0148] Afterwards, the control effect can be evaluated. For example, dynamic layer verification can be performed, as shown below:

[0149] If the controlled voltage does not enter the target range, a secondary adjustment is triggered.

[0150] Evaluation metric: Transient overshoot rate .in, This represents the peak value of the transient overvoltage. This is the steady-state voltage value.

[0151] Steady-state layer verification can also be performed. After power flow convergence, check the node voltage over-limit situation. If over-limit situation exists, redistribute reactive power output.

[0152] In addition to evaluating the control effect, adaptive PID coefficients can also be used.

[0153] In some other embodiments of this specification, the power system control effect is verified based on a dynamic-steady-state hybrid model, and the control strategy is adaptively adjusted according to the actual situation of the power system. This may include the construction of a simulation verification platform and hardware deployment. The construction of the simulation verification platform includes:

[0154] (1) Software tool integration:

[0155] Dynamic simulation: PSCAD 4.6 + custom component library (synchronous machine, STATCOM, wind power model, etc.);

[0156] Steady-state calculation: BPA 4.2+ Python interface (calling bpa_api.dll for parameter injection);

[0157] Cooperative control: FPGA logic simulation implemented using MATLAB / Simulink;

[0158] (2) Hardware-in-the-loop (HIL):

[0159] Real-time simulator: RT-LAB OP4500 (50μs step), connected to an actual SVC controller (such as ABB PCS6000).

[0160] Communication protocol: IEC 61850-9-2 LE (sampled value) and GOOSE (control command).

[0161] Hardware deployment may include:

[0162] Control terminal installation:

[0163] FPGA board: Xilinx Kintex-7 XC7K325T, used for impedance calculation logic;

[0164] Communication module: Hirschmann MACH4002 switch (supports IEEE 1588 PTP).

[0165] Field wiring specifications:

[0166] PMU voltage / current input: Shielded twisted pair cable (cross-sectional area ≥ 2.5mm²), grounding resistance < 1Ω;

[0167] GOOSE output: Fiber optic interface (LC type), transmission delay <2ms.

[0168] The invention will now be illustrated by a specific example. A power grid in a real-world renewable energy aggregation area is shown below. Figure 2 As shown. Initial state: All 7 wind farms are operating at full capacity, the active power flow of the 500kV DLS~CKS double-circuit line is 3042MW, the voltage of the DLS station is U1=520.3kV, and the voltage of the CKS station is U2=519.4kV. At 0.2s, the 500kV DLS~CKS line 1 undergoes maintenance, and the 500kV DLS~CKS line 2 on the CKS side sheds load.

[0169] Traditional electromagnetic transient modeling method: Based on PSCAD software, 500kV BZ station, 500kV CKS station, 500kV DLS station, 500kV WC station, and 500kV HT station are selected as isostat points for Thevenin isostating. The lines between isostat points are modeled using the Bergeron model, and the new energy power stations are all isostated in the BZ station.

[0170] If the traditional method is used to perform load shedding operations on the CKS side of the 500kV DLS~CKS line in the PSCAD Thevenin equivalent model and BPA power flow software respectively, the voltage at the end of the line exceeds the dispatch-specified 550kV after load shedding, requiring pre-control of the DLS bus voltage at the beginning of the line. As the power flow of the 500kV DLS~CKS line decreases, the control voltage of the DLS bus at the beginning of the line calculated in PSCAD and BPA power flow software is shown in Table 1 below.

[0171] Table 1

[0172]

[0173] The calculation results above show that in PSCAD calculations, the heavier the line power flow, the lower the control voltage of the head bus after the load is shed at the end. However, in BPA power flow calculations, the heavier the line power flow, the higher the control voltage of the head bus after the load is shed at the end. This shows a contradiction between the two.

[0174] Using the method of this invention, key nodes are first selected in PSCAD for detailed modeling. This mainly includes the new energy power stations involved in the grid structure, which require detailed doubly fed wind turbine models, as well as the STATCOM / SVC configuration of the new energy power stations, which also need to be modeled in detail in PSCAD.

[0175] Then import the initial power flow results from the BPA (.dat file) and configure the PMU virtual sampling points (head-end DLS bus, new energy grid connection point BZ station). At t=0.2s, load shedding is triggered, with an action duration of t=0.1s, and data is exported from PSCAD every 5ms. , The BPA card is updated via a Python script. If BPA converges, the new voltage source is read and sent back to PSCAD. Using the method of this invention, as the power flow of the 500kV DLS~CKS line decreases, the control voltage of the DLS bus at the beginning of the line calculated in PSCAD is shown in Table 2 below, thus avoiding the above-mentioned problems.

[0176] Table 2

[0177]

[0178] Based on the same general inventive concept, this invention also protects a power system voltage control device based on dynamic steady-state cooperative correction, such as... Figure 3 As shown, Figure 3 This is a schematic diagram of the power system voltage control device based on dynamic steady-state collaborative correction provided in an embodiment of the present invention. The power system voltage control device based on dynamic steady-state collaborative correction provided by the present invention will be described below. The power system voltage control device based on dynamic steady-state collaborative correction described below can be referred to in correspondence with the power system voltage control method based on dynamic steady-state collaborative correction described above.

[0179] The power system voltage control device based on dynamic steady-state collaborative correction includes a dynamic steady-state module 301, a parameter update module 302, a voltage graded control module 303, and a verification module 304.

[0180] The dynamic steady-state module 301 is used to establish an electromagnetic transient model for a preset voltage node in the power system electromagnetic transient simulation software PSCAD, simplify the power grid with an electrical distance to the target area that exceeds the preset distance into a dynamic Thevenin equivalent model, initialize the power flow calculation in BPA, set the generator as a PV node and the load as a PQ node, configure the reactive power compensation equipment parameters, and obtain a dynamic-steady-state hybrid model.

[0181] The parameter update module 302 is used to update the dynamic Thevenin equivalent parameters of the power system in real time based on the data of the power system phasor measurement unit and synchronize them to the BPA;

[0182] The voltage graded control module 303 is used to suppress transient overvoltages in the power system within a time period of less than a first preset time period based on a dynamic-steady-state hybrid model, and to optimize the steady-state voltage of the power system within a time period of less than a second preset time period in combination with wide-area coordinated control.

[0183] The verification module 304 is used to verify the control effect of the power system based on the dynamic-steady-state hybrid model, and to adaptively adjust the control strategy according to the actual situation of the power system.

[0184] Figure 4 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention.

[0185] like Figure 4 As shown, the electronic device may include a processor 410, a communication interface 420, a memory 430, and a communication bus 440. The processor 410, communication interface 420, and memory 430 communicate with each other via the communication bus 440. The processor 410 can call logic instructions from the memory 430 to execute a power system voltage control method based on dynamic steady-state collaborative correction.

[0186] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0187] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the power system voltage control method based on dynamic steady-state collaborative correction provided by the above methods.

[0188] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the power system voltage control method based on dynamic steady-state cooperative correction provided by the above methods.

[0189] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0190] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0191] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power system voltage control method based on dynamic steady-state collaborative correction, characterized in that, include: In the power system electromagnetic transient simulation software PSCAD, an electromagnetic transient model is established for the preset voltage nodes. The power grid with an electrical distance to the target area exceeding the preset distance is simplified into a dynamic Thevenin equivalent model. Power flow calculation is initialized in BPA, generators are set as PV nodes and loads are set as PQ nodes. The parameters of reactive power compensation equipment are configured to obtain a dynamic-steady-state hybrid model. The dynamic Thevenin equivalent parameters of the power system are updated in real time based on the data from the power system phasor measurement unit and synchronized to the BPA; Based on the dynamic-steady-state hybrid model, transient overvoltages in the power system are suppressed within a time period less than the first preset time period, and the steady-state voltage of the power system is optimized within a time period less than the second preset time period by combining wide-area coordinated control. Based on a dynamic-steady-state hybrid model, the control effect of the power system is verified, and the control strategy is adaptively adjusted according to the actual situation of the power system. In the power system electromagnetic transient simulation software PSCAD, electromagnetic transient models are established for preset voltage nodes. Power grids with electrical distances exceeding preset distances to the target area are simplified into dynamic Thevenin equivalent models, including: Calculate the voltage sensitivity of each voltage node in the power system to power changes, and analyze the topology of the power system. Based on the sensitivity and topology, the preset voltage nodes are obtained. Configure the model parameters of the electromagnetic transient model based on the parameter file of BPA to ensure that the model parameters are consistent with the steady-state data of BPA. For power grids whose electrical distance to the target area exceeds a preset distance, the equivalent impedance and equivalent voltage source are calculated using the short-circuit capacity method or the N-1 fault scanning method to obtain a dynamic Thevenin equivalent model. Suppressing transient overvoltages in the power system for a period of less than a first preset time includes: When a transient overvoltage peak is detected to exceed the first preset voltage threshold or the voltage change rate exceeds the preset change threshold, the reactive power output is calculated based on the preset proportional gain, integral gain and reserved safety margin in order to quickly respond to and suppress the transient overvoltage. When the steady-state voltage deviation exceeds the second preset voltage threshold and the duration exceeds the first preset duration threshold, the step size is adjusted according to a preset ratio. If the number of adjustments reaches the preset number within the preset time period, the blocking condition is activated. Optimizing the steady-state voltage of the power system within a time period less than a second preset duration by combining wide-area coordinated control includes: Calculate the reactive power sensitivity of each generator to the head-end voltage, select the two units with the highest sensitivity, and adjust the excitation voltage command according to the voltage deviation and the preset automatic voltage regulator proportional gain. When the voltage is lower than the third preset voltage threshold for a duration exceeding the second preset duration, and all reactive power resources have been exhausted, load shedding is performed according to priority and gradient.

2. The power system voltage control method based on dynamic steady-state collaborative correction according to claim 1, characterized in that, The sensitivity of voltage nodes to power changes in a power system is calculated, and the topology of the power system is analyzed. Based on the sensitivity and topology, preset voltage nodes are obtained, including: Calculate the ratio of voltage to corresponding power at each voltage node in the power system, as the sensitivity. Sort the sensitivities from smallest to largest; According to the sorting, select a preset number of voltage nodes corresponding to the sensitivity, as well as voltage nodes located in the backbone network, new energy aggregation point and load center in the topology as preset voltage nodes.

3. The power system voltage control method based on dynamic steady-state collaborative correction according to claim 1, characterized in that, The equivalent impedance is calculated using the short-circuit capacity method, including: Based on the power flow calculation results, the short-circuit capacity is obtained; Calculate the ratio of the square of the grid connection point voltage to the short-circuit capacity, and use it as the equivalent impedance; The equivalent impedance is calculated using the N-1 fault scan method, including: Simulate a three-phase short-circuit fault at a preset node in PSCAD to obtain the fault current; Calculate the ratio of the voltage before the fault to the fault current, and use it as the equivalent impedance.

4. The power system voltage control method based on dynamic steady-state collaborative correction according to claim 1, characterized in that, The dynamic Thevenin equivalent parameters of the power system are updated in real time based on data from the power system phasor measurement unit and synchronized to the BPA, including: Samples are taken from preset nodes in the power system to obtain voltage and current sampling data; Preprocess the sampled data; Based on the preprocessed sampling data, the dynamic Thevenin equivalent parameters are updated in real time using the sensitivity method. The updated dynamic Thevenin equivalent parameters are synchronized to BPA via the data interface.

5. The power system voltage control method based on dynamic steady-state collaborative correction according to claim 4, characterized in that, The dynamic Thevenin equivalent parameters are updated in real time using the sensitivity method, including: The sensitivity method is used to compare the voltage and current changes in the current cycle with those in the previous cycle. Determine the ratio of voltage change to current change as the impedance change; The updated equivalent impedance is obtained based on the impedance change, the smoothing coefficient of the impedance change, and the equivalent impedance of the previous period. The updated voltage value is obtained based on the updated equivalent impedance and the current and voltage values ​​of the current cycle.

6. The power system voltage control method based on dynamic steady-state collaborative correction according to claim 5, characterized in that, The change in impedance is expressed by the following formula: ； in, The change in impedance. This is the voltage value from the previous cycle. The current value is from the previous cycle, and k represents the cycle. This is the voltage value for the current cycle. This represents the current value for the current cycle. The updated equivalent impedance is expressed by the following formula: ； For the updated equivalent impedance, This is the equivalent impedance of the previous cycle. This is the smoothing coefficient.

7. The power system voltage control method based on dynamic steady-state collaborative correction according to claim 4, characterized in that, The updated dynamic Thevenin equivalent parameters will be synchronized to BPA via the data interface, including: The updated dynamic Thevenin equivalent parameters are synchronized to BPA by calling the BPA interface through a Python script; If the rate of change of parameter impedance and the phase change of voltage source reach the set threshold after BPA update, then power flow recalculation is performed. Read the generator voltage setting and reactive power compensation command output by BPA and send them back to PSCAD.

8. A power system voltage control device based on dynamic steady-state collaborative correction, characterized in that, include: The dynamic steady-state module is used to establish electromagnetic transient models for preset voltage nodes in the power system electromagnetic transient simulation software PSCAD, simplify the power grid with an electrical distance to the target area that exceeds the preset distance into a dynamic Thevenin equivalent model, initialize power flow calculation in BPA, set generators as PV nodes and loads as PQ nodes, configure reactive power compensation equipment parameters, and obtain a dynamic-steady-state hybrid model. The parameter update module is used to update the dynamic Thevenin equivalent parameters of the power system in real time based on the data from the power system phasor measurement unit and synchronize them to the BPA. The voltage graded control module is used to suppress transient overvoltages in the power system within a time period of less than a first preset time period based on a dynamic-steady-state hybrid model, and to optimize the steady-state voltage of the power system within a time period of less than a second preset time period in combination with wide-area coordinated control. The verification module is used to verify the control effect of the power system based on the dynamic-steady-state hybrid model, and to adaptively adjust the control strategy according to the actual situation of the power system. In the power system electromagnetic transient simulation software PSCAD, electromagnetic transient models are established for preset voltage nodes. Power grids with electrical distances exceeding preset distances to the target area are simplified into dynamic Thevenin equivalent models, including: Calculate the voltage sensitivity of each voltage node in the power system to power changes, and analyze the topology of the power system. Based on the sensitivity and topology, the preset voltage nodes are obtained. Configure the model parameters of the electromagnetic transient model based on the parameter file of BPA to ensure that the model parameters are consistent with the steady-state data of BPA. For power grids whose electrical distance to the target area exceeds a preset distance, the equivalent impedance and equivalent voltage source are calculated using the short-circuit capacity method or the N-1 fault scanning method to obtain a dynamic Thevenin equivalent model. Suppressing transient overvoltages in the power system for a period of less than a first preset time includes: When a transient overvoltage peak is detected to exceed the first preset voltage threshold or the voltage change rate exceeds the preset change threshold, the reactive power output is calculated based on the preset proportional gain, integral gain and reserved safety margin in order to quickly respond to and suppress the transient overvoltage. When the steady-state voltage deviation exceeds the second preset voltage threshold and the duration exceeds the first preset duration threshold, the step size is adjusted according to a preset ratio. If the number of adjustments reaches the preset number within the preset time period, the blocking condition is activated. Optimizing the steady-state voltage of the power system within a time period less than a second preset duration by combining wide-area coordinated control includes: Calculate the reactive power sensitivity of each generator to the head-end voltage, select the two units with the highest sensitivity, and adjust the excitation voltage command according to the voltage deviation and the preset automatic voltage regulator proportional gain. When the voltage is lower than the third preset voltage threshold for a duration exceeding the second preset duration, and all reactive power resources have been exhausted, load shedding is performed according to priority and gradient.

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