Method and system for converting simulation model of static load of power system

Abstract

The application discloses a simulation model conversion method of static load of a power system, which comprises the following steps: obtaining data information of static load in electromechanical transient simulation; measuring voltage and frequency in real time and calculating frequency change value; calculating power data and impedance data of a current static load model; updating once every set time; in the process of electromagnetic transient simulation, keeping the impedance data of the static load model constant within the set time before simulation, and starting electromagnetic transient simulation, thereby completing the simulation model conversion of static load of the power system. The application further discloses a system for realizing the simulation model conversion of static load of the power system. The application realizes static load power fluctuation caused by voltage change by changing static load impedance value, guarantees that the dynamic response characteristics of static load in electromagnetic transient simulation are consistent with electromechanical transient simulation, and therefore, the application has higher reliability, better accuracy and better effect.

Description

Technical Field

[0001] This invention belongs to the field of electrical automation, and specifically relates to a method and system for converting simulation models of static loads in power systems. Background Technology

[0002] With economic and technological development and the improvement of people's living standards, electricity has become an indispensable secondary energy source in people's production and daily life, bringing endless convenience. Therefore, ensuring a stable and reliable supply of electricity has become one of the most important tasks of the power system.

[0003] Currently, the operating conditions of power systems are becoming increasingly complex. To improve the safety and reliability of power systems, it is necessary to study the characteristics of power systems under specific conditions, both during the planning and operation phases. Therefore, it is essential to construct corresponding simulation models for various types of power system loads. Static load is one of the most typical traditional load models for power systems, and it is extremely common and important in power system simulation.

[0004] Electromechanical transient simulation has wide applications in power system planning, design, and dispatching, accurately simulating the dynamic characteristics of static loads by obtaining precise voltage amplitude and angle at all times. Full electromagnetic transient simulation also has relatively wide applications in power systems, and it also requires an accurate static load model. However, unlike electromechanical transient simulation, full electromagnetic transient simulation cannot calculate the voltage amplitude and angle of the static load at all times; therefore, this affects the simulation and analysis process of power systems to some extent. Summary of the Invention

[0005] One of the objectives of this invention is to provide a simulation model conversion method for static loads in power systems that is highly reliable, accurate, and effective.

[0006] The second objective of this invention is to provide a system for implementing the simulation model conversion method for static load of the power system.

[0007] The simulation model conversion method for static load of a power system provided by this invention includes the following steps:

[0008] S1. Obtain data information of static load in electromechanical transient simulation;

[0009] S2. During the simulation, based on the data obtained in step S1, the voltage and frequency of the static load model are measured in real time in the electromechanical transient simulation, and the frequency change value is calculated.

[0010] S3. Based on the data obtained in step S2, calculate the power data of the current static load model in the electromechanical transient simulation;

[0011] S4. Based on the data obtained in step S3, calculate the impedance data of the current static load model in the electromechanical transient simulation;

[0012] S5. Update the impedance data calculated in step S4 at set intervals.

[0013] S6. Based on the data obtained in step S5, during the electromagnetic transient simulation, the impedance data of the static load model is kept constant within the set time before the simulation, and the corresponding electromagnetic transient simulation is started to complete the simulation model conversion of the power system static load.

[0014] Step S1, which involves obtaining data information on static loads in electromechanical transient simulation, specifically includes the following steps:

[0015] Acquire the static load data information in the electromechanical transient simulation; the data information includes the initial operating voltage V0, initial operating active power P0, initial operating reactive power Q0, reference frequency f0, constant impedance active load proportional coefficient A1, constant current active load proportional coefficient A2, constant power active load proportional coefficient A3, active power change percentage coefficient A4 caused by a 1% frequency change, constant impedance reactive load proportional coefficient B1, constant current reactive load proportional coefficient B2, constant power reactive load proportional coefficient B3, and reactive power change percentage coefficient B4 caused by a 1% frequency change; at the same time, A1+A2+A3=1.0, B1+B2+B3=1.0.

[0016] In the simulation process described in step S2, based on the data information obtained in step S1, the voltage and frequency of the static load model are measured in real time in the electromechanical transient simulation, and the frequency change value is calculated. Specifically, the process includes the following steps:

[0017] The voltage of the static load model measured in real time during electromechanical transient simulation is obtained using the following formula:

[0018]

[0019] In the formula, V is the effective value of the phase line voltage of the static load model measured in real time during electromechanical transient simulation; V a This refers to the instantaneous value of phase A voltage in a static load model measured in real time during electromechanical transient simulation; V b This refers to the instantaneous value of phase B voltage in the static load model measured in real time during electromechanical transient simulation; V c This refers to the instantaneous C-phase voltage value of the static load model measured in real time during electromechanical transient simulation.

[0020] The measured instantaneous values ​​of the three-phase voltage are passed through a phase-locked loop (PLL) to obtain the frequency f of the static load model measured in real time during electromechanical transient simulation.

[0021] Subtracting the obtained frequency f from the reference frequency f0 yields the frequency change Δf.

[0022] Step S3, which involves calculating the power data of the current static load model in the electromechanical transient simulation based on the data information obtained in step S2, specifically includes the following steps:

[0023] The power data for the current static load model is calculated using the following formula:

[0024]

[0025] In the formula, P represents the active power data of the current static load model; Q represents the reactive power data of the current static load model.

[0026] Step S4, which involves calculating the impedance data of the current static load model in the electromechanical transient simulation based on the data information obtained in step S3, specifically includes the following steps:

[0027] The impedance data of the current static load model is calculated using the following formula:

[0028]

[0029] In the formula Z * R is the impedance value of the current static load model; R is the resistance value of the current static load model, and X is the reactance value of the current static load model, and S represents the apparent power of the current static load model;

[0030] If the reactive power Q in the current static load model is positive, then the corresponding inductance value L is calculated as follows: If the reactive power Q in the current static load model is negative, then the corresponding capacitance value C is calculated as follows:

[0031] Step S5 involves updating the impedance data calculated in step S4 at set time intervals, specifically including the following steps:

[0032] The impedance data obtained in step S4 is updated every half cycle to improve the simulation speed.

[0033] Step S6, based on the data obtained in step S5, involves maintaining the impedance data of the static load model constant within a set time before the electromagnetic transient simulation and then starting the corresponding electromagnetic transient simulation to complete the simulation model conversion of the power system static load. Specifically, this includes the following steps:

[0034] Obtain the impedance data information obtained in step S5, keep the impedance data of the static load model constant for 1 second before the start of the electromagnetic transient simulation process, and start the corresponding electromagnetic transient simulation to complete the simulation model conversion of the power system static load.

[0035] This invention also provides a system for implementing the simulation model conversion method for the static load of the power system, comprising a data acquisition module, a data measurement module, a power calculation module, an impedance calculation module, an impedance update module, and a model conversion module; the data acquisition module, data measurement module, power calculation module, impedance calculation module, impedance update module, and model conversion module are connected in series; the data acquisition module is used to acquire the data information of the static load in the electromechanical transient simulation and upload the data to the data measurement module; the data measurement module is used to measure the voltage and frequency of the static load model in real time during the electromechanical transient simulation based on the received data, calculate the frequency change value, and upload the data to the power calculation module; the power calculation module... The first module calculates the power data of the current static load model in electromechanical transient simulation based on the received data and uploads the data to the impedance calculation module. The second module calculates the impedance data of the current static load model in electromechanical transient simulation based on the received data and uploads the data to the impedance update module. The third module updates the calculated impedance data at set intervals based on the received data and uploads the data to the model conversion module. The fourth module maintains the impedance data of the static load model constant for a set time before the electromagnetic transient simulation and starts the corresponding electromagnetic transient simulation, thus completing the simulation model conversion of the power system static load.

[0036] The simulation model conversion method and system for static loads in power systems provided by this invention realizes the power fluctuation of static loads caused by voltage changes by changing the static load impedance value, ensuring that the dynamic response characteristics of static loads in electromagnetic transient simulation are consistent with those in electromechanical transient simulation; therefore, this invention has higher reliability, better accuracy, and better effect. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0038] Figure 2 This is a schematic diagram of the simulation results of an embodiment of the method of the present invention.

[0039] Figure 3 This is a schematic diagram of the functional modules of the system of the present invention. Detailed Implementation

[0040] like Figure 1The diagram shown is a flowchart of the method of the present invention: The simulation model conversion method for static load of a power system provided by the present invention includes the following steps:

[0041] S1. Obtain data information of static load in electromechanical transient simulation; specifically including the following steps:

[0042] Acquire static load data information from electromechanical transient simulation; the data information includes initial operating voltage V0, initial operating active power P0, initial operating reactive power Q0, reference frequency f0, constant impedance active load proportionality coefficient A1, constant current active load proportionality coefficient A2, constant power active load proportionality coefficient A3, active power change percentage coefficient A4 caused by 1% frequency change, constant impedance reactive load proportionality coefficient B1, constant current reactive load proportionality coefficient B2, constant power reactive load proportionality coefficient B3, and reactive power change percentage coefficient B4 caused by 1% frequency change; simultaneously, A1+A2+A3=1.0, B1+B2+B3=1.0;

[0043] S2. During the simulation, based on the data obtained in step S1, the voltage and frequency of the static load model are measured in real time in the electromechanical transient simulation, and the frequency change value is calculated; specifically, the following steps are included:

[0044] The voltage of the static load model measured in real time during electromechanical transient simulation is obtained using the following formula:

[0045]

[0046] In the formula, V is the effective value of the phase line voltage of the static load model measured in real time during electromechanical transient simulation; V a This refers to the instantaneous value of phase A voltage in a static load model measured in real time during electromechanical transient simulation; V b This refers to the instantaneous value of phase B voltage in the static load model measured in real time during electromechanical transient simulation; V c This refers to the instantaneous C-phase voltage value of the static load model measured in real time during electromechanical transient simulation.

[0047] The measured instantaneous values ​​of the three-phase voltage are passed through a phase-locked loop (PLL) to obtain the frequency f of the static load model measured in real time during electromechanical transient simulation.

[0048] Subtract the obtained frequency f from the reference frequency f0 to obtain the frequency change Δf;

[0049] S3. Based on the data obtained in step S2, calculate the power data of the current static load model in the electromechanical transient simulation; specifically including the following steps:

[0050] The power data for the current static load model is calculated using the following formula:

[0051]

[0052] In the formula, P represents the active power data of the current static load model; Q represents the reactive power data of the current static load model.

[0053] S4. Based on the data obtained in step S3, calculate the impedance data of the current static load model in the electromechanical transient simulation; specifically including the following steps:

[0054] The impedance data of the current static load model is calculated using the following formula:

[0055]

[0056] In the formula Z * R is the impedance value of the current static load model; R is the resistance value of the current static load model, and X is the reactance value of the current static load model, and S represents the apparent power of the current static load model;

[0057] If the reactive power Q in the current static load model is positive, then the corresponding inductance value L is calculated as follows: If the reactive power Q in the current static load model is negative, then the corresponding capacitance value C is calculated as follows:

[0058] S5. Update the impedance data calculated in step S4 every set time interval; update the impedance data of the current static load model every half cycle to improve the simulation speed.

[0059] S6. Based on the data obtained in step S5, during the electromagnetic transient simulation, the impedance data of the static load model is kept constant for a set time before the simulation, and the corresponding electromagnetic transient simulation is started to complete the simulation model conversion of the power system static load; specifically, the following steps are included:

[0060] Obtain the impedance data information obtained in step S5, keep the impedance data of the static load model constant for 1 second before the start of the electromagnetic transient simulation process, and start the corresponding electromagnetic transient simulation to complete the simulation model conversion of the power system static load.

[0061] The method of the present invention will be further described below with reference to an embodiment:

[0062] In the IEEE 9-bus AC system, the electromechanical data of a certain static load in the PSD are shown in Table 1:

[0063] Table 1. Schematic diagram of electromechanical transient simulation data for a static load in IEEE 9.

[0064] Reference frequency / Hz 50 Active power per MW 125 Reactive power per load / MVar 70 Percentage of active load with constant impedance 0.4 Percentage of constant impedance reactive load 0.4 Percentage of constant current active load 0.3 Percentage of constant current reactive load 0.3 Percentage of constant power active load 0.3 Percentage of constant power reactive load 0.3

[0065] Based on the method of this invention, after the electromechanical to electromagnetic transient simulation model conversion, the electromagnetic transient data file of the generated static load model is shown in Table 2 below. The initial voltage is the effective value of the line voltage of the static load during steady-state operation of the PSD electromechanical simulation. A3 represents the percentage of constant power active load, A2 represents the percentage of constant current active load, and the percentage of constant impedance active load A1 is obtained by 1-A2-A3; B3 represents the percentage of constant power reactive load, B2 represents the percentage of constant current reactive load, and the percentage of constant impedance reactive load is obtained by 1-Kqc-Kqi; specific data are shown in Table 2.

[0066] Table 2. Data illustration of the static load in electromagnetic transient simulation.

[0067] Reference frequency / Hz 50 Initial load active power / MW 125 Initial load reactive power / MVar 70 <![CDATA[A3]]> 0.3 <![CDATA[A2]]> 0.3 <![CDATA[A1]]> 0.4 <![CDATA[B3]]> 0.3 <![CDATA[B2]]> 0.3 <![CDATA[B1]]> 0.4

[0068] A three-phase transient ground fault occurs on a busbar in the system at simulation time 3s, with a fault duration of 0.01s. The final electromagnetic transient simulation results and electromechanical transient simulation results of the active and reactive power of this static load are compared as follows: Figure 2 As shown;

[0069] from Figure 2 It can be seen that, under the static load model proposed by the method of this invention, the dynamic response characteristics of the static load in electromagnetic transient simulation are basically consistent with those in electromechanical transient simulation.

[0070] like Figure 3The diagram shows the functional modules of the system of the present invention: The system disclosed in this invention for realizing the simulation model conversion method of the static load of the power system includes a data acquisition module, a data measurement module, a power calculation module, an impedance calculation module, an impedance update module, and a model conversion module; the data acquisition module, data measurement module, power calculation module, impedance calculation module, impedance update module, and model conversion module are connected in series; the data acquisition module is used to acquire the data information of the static load in the electromechanical transient simulation and upload the data to the data measurement module; the data measurement module is used to measure the voltage and frequency of the static load model in real time during the simulation process based on the received data, calculate the frequency change value, and upload the data to the power calculation module. The system consists of several modules: a power calculation module, an impedance calculation module, and a model conversion module. The power calculation module calculates the power data of the current static load model based on the received data during electromechanical transient simulation and uploads the data to the impedance update module. The impedance update module updates the calculated impedance data at set intervals based on the received data and uploads the data to the model conversion module. The model conversion module maintains the impedance data of the static load model constant for a set time before the electromagnetic transient simulation and starts the corresponding electromagnetic transient simulation, thus completing the simulation model conversion of the power system static load.

Claims

1. A method for converting a simulation model of static load in a power system, comprising the following steps: S1. Obtain data information of static load in electromechanical transient simulation; S2. During the simulation, based on the data obtained in step S1, the voltage and frequency of the static load model are measured in real time in the electromechanical transient simulation, and the frequency change value is calculated. S3. Based on the data obtained in step S2, calculate the power data of the current static load model in the electromechanical transient simulation; S4. Based on the data obtained in step S3, calculate the impedance data of the current static load model in the electromechanical transient simulation; specifically including the following steps: The impedance data of the current static load model is calculated using the following formula: In the formula This represents the impedance value of the current static load model; Let be the resistance value of the current static load model, and ; Let be the reactance value of the current static load model, and ; This represents the apparent power of the current static load model; This refers to the effective value of the phase line voltage of the static load model measured in real time during electromechanical transient simulation. This refers to the active power data of the current static load model; This refers to the reactive power data of the current static load model; If the reactive power of the current static load model If the value is positive, the corresponding inductance value is calculated. for If the reactive power of the current static load model If the value is negative, the corresponding capacitance value is calculated. for ; The frequency of the static load model measured in real time during electromechanical transient simulation; S5. Update the impedance data calculated in step S4 at set intervals; S6. Based on the data obtained in step S5, during the electromagnetic transient simulation, the impedance data of the static load model is kept constant within the set time before the simulation, and the corresponding electromagnetic transient simulation is started to complete the simulation model conversion of the power system static load.

2. The method for converting the simulation model of static load in a power system according to claim 1, characterized in that... Step S1, which involves obtaining data information on static loads in electromechanical transient simulation, specifically includes the following steps: Acquire data information of static load in electromechanical transient simulation; the data information includes initial operating voltage. Initial operating active power Initial operating reactive power Reference frequency Constant impedance active load proportionality coefficient Constant current active load proportionality coefficient Constant power active load ratio factor Percentage coefficient of active power change caused by a 1% change in frequency Constant impedance reactive load proportionality coefficient Constant current reactive load proportionality coefficient Constant power reactive load ratio factor The percentage coefficient of reactive power change caused by a 1% change in frequency ;at the same time, , .

3. The method for converting the simulation model of static load in a power system according to claim 2, characterized in that... In the simulation process described in step S2, based on the data information obtained in step S1, the voltage and frequency of the static load model are measured in real time in the electromechanical transient simulation, and the frequency change value is calculated. Specifically, the process includes the following steps: The voltage of the static load model measured in real time during electromechanical transient simulation is obtained using the following formula: In the formula This refers to the effective value of the phase line voltage of the static load model measured in real time during electromechanical transient simulation. This refers to the instantaneous value of phase A voltage in the static load model, measured in real time during electromechanical transient simulation. This refers to the instantaneous value of phase B voltage in the static load model, measured in real time during electromechanical transient simulation. This refers to the instantaneous C-phase voltage value of the static load model measured in real time during electromechanical transient simulation. The measured instantaneous values ​​of the three-phase voltage are passed through a phase-locked loop (PLL) to obtain the frequency of the static load model measured in real time during electromechanical transient simulation. ; The obtained frequency With reference frequency Subtracting them gives the change in frequency. .

4. The method for converting the simulation model of static load in a power system according to claim 3, characterized in that... Step S3, which involves calculating the power data of the current static load model in the electromechanical transient simulation based on the data information obtained in step S2, specifically includes the following steps: The power data for the current static load model is calculated using the following formula: In the formula This refers to the active power data of the current static load model; This refers to the reactive power data of the current static load model.

5. The method for converting the simulation model of static load in a power system according to claim 4, characterized in that... Step S5 involves updating the impedance data calculated in step S4 at set time intervals, specifically including the following steps: The impedance data obtained in step S4 is updated every half cycle to improve the simulation speed.

6. The method for converting the simulation model of static load in a power system according to claim 5, characterized in that... Step S6, based on the data obtained in step S5, involves maintaining the impedance data of the static load model constant within a set time before the electromagnetic transient simulation and then starting the corresponding electromagnetic transient simulation to complete the simulation model conversion of the power system static load. Specifically, this includes the following steps: Obtain the impedance data information obtained in step S5, keep the impedance data of the static load model constant for 1 second before the start of the electromagnetic transient simulation process, and start the corresponding electromagnetic transient simulation to complete the simulation model conversion of the power system static load.

7. A system for implementing the simulation model conversion method for static load of a power system as described in any one of claims 1 to 6, characterized in that... It includes a data acquisition module, a data measurement module, a power calculation module, an impedance calculation module, an impedance update module, and a model conversion module; these modules are connected in series. The data acquisition module acquires the static load data information in the electromechanical transient simulation and uploads the data to the data measurement module. The data measurement module measures the voltage and frequency of the static load model in real time during the electromechanical transient simulation based on the received data, calculates the frequency change value, and uploads the data to the power calculation module. The power calculation module calculates the power data of the current static load model in the electromechanical transient simulation based on the received data and uploads the data to the impedance calculation module. The impedance calculation module is used to calculate the impedance data of the current static load model in electromechanical transient simulation based on the received data, and upload the data to the impedance update module. The impedance update module is used to update the calculated impedance data every set time period based on the received data, and then upload the data to the model conversion module. The model conversion module is used to maintain the impedance data of the static load model constant within a set time before the electromagnetic transient simulation, based on the received data, and then start the corresponding electromagnetic transient simulation to complete the simulation model conversion of the power system static load.

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