Active networking control method for high-proportion renewable energy clusters based on PMU

Abstract

The present invention provides a PMU-based high-proportion renewable energy cluster active networking control method, which belongs to the energy field and includes: the power grid dispatching center distributes the active output that each distributed energy generator set should bear through cluster optimization control; performs active output correction; combines active droop control with an active output correction module, so that each distributed energy generator set ignores the droop coefficient and the output active output reaches any active output reference value. The present invention realizes arbitrary control of the active output of each generator set without changing the active droop control coefficient, highlighting the flexibility of power electronic devices.

Description

Technical Field

[0001] The present invention belongs to the field of energy, and in particular relates to a PMU (synchronous phasor measurement unit)-based active networking control method for a high-proportion renewable energy cluster. Background Art

[0002] With the large-scale development of renewable energy power generation, renewable energy itself has the defects of volatility and intermittency, and the impact of renewable energy access to the grid on the system. At present, there are problems of mismatch between power supply, grid and load in renewable energy power generation. There is a lack of new power system cluster control dominated by power electronic control, and it is impossible to achieve renewable energy fluctuation smoothing on the power generation side, resulting in large-scale "wind abandonment" and "light abandonment" phenomena. At present, the grid-type active power-phase angle droop control is subject to the droop coefficient to distribute the active power output of each unit. It is impossible to respond to the upper-level dispatching instructions in time when the load changes, and it is impossible to reflect the real-time and arbitrary nature of the power electronic control of distributed energy units. Summary of the invention

[0003] In order to solve the problem that the current active power droop control of grid-type converters is limited to distributing the active power output of each unit according to the droop coefficient, and cannot arbitrarily adjust the active power output of each unit according to the cluster optimization control instructions when the load changes, the present invention provides an active grid-forming control method for a high-proportion renewable energy cluster based on PMU, which is an "active power output correction" method for active power droop control of grid-forming converters based on distributed energy cluster control of PMU.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] The active networking control method of a high-proportion renewable energy cluster based on PMU includes the following steps:

[0006] Step 1: The grid dispatching center allocates the active output P that each distributed energy generator should bear through cluster optimization control refi ;

[0007] Step 2: Perform active output correction, including active output phase angle correction and active output voltage correction, which is achieved through the active output phase angle correction module and the active output voltage correction module; the active output phase angle correction module outputs the phase angle correction reference value based on the PMU data The active output voltage correction module outputs voltage correction reference value based on PMU data ;

[0008] Step 3: Combine the active power droop control with the active power output correction module to make each distributed energy generator ignore the droop coefficient and output active power to any active power reference value. ; The active power droop control includes active power-phase angle droop control and active power-voltage droop control, and the active power output correction module is divided into an active power output phase angle correction module and an active power output voltage correction module; when the line impedance is inductive, the active power-phase angle droop control is combined with the active power output phase angle correction module; when the line impedance is resistive, the active power-voltage droop control is combined with the active power output voltage correction module; when the line impedance is inductive, the active power output reference value is ; When the line impedance is resistive, the active output reference value is .

[0009] Beneficial effects:

[0010] 1. The present invention realizes arbitrary control of the active power output of each generator set without changing the active power droop control coefficient, highlighting the flexibility of power electronic devices.

[0011] 2. The PMU-based distributed energy cluster control model proposed in the present invention enables each distributed power generation new energy unit to respond to the active upper-level dispatching instructions, realizes cluster coordinated control of the regional power grid, reduces the "wind abandonment" and "solar abandonment" phenomena, and ensures the support of the power system of distributed energy power generation for frequency, thereby ensuring the stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The present invention provides a flow chart of a method for actively controlling a high-proportion renewable energy cluster based on PMU. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0014] like Figure 1 As shown, the active networking control method of a high-proportion renewable energy cluster based on PMU of the present invention comprises the following steps:

[0015] Step 1: The grid dispatching center allocates the active power output of each distributed energy generator through cluster optimization control , distributed energy generators include wind turbines, photovoltaic units and energy storage units, including:

[0016] Step 11: Establish a PMU-based wide-area measurement system for new energy distributed power generation in the power grid dispatching center to monitor the real-time data of each distributed energy generator set.

[0017] When the line impedance between the converter and the load (hereinafter referred to as "line impedance") is inductive, the effective value of the AC output line voltage of the converter of the i-th distributed energy generator DGi is measured. And the inverter AC output line voltage phase angle , line reactance X i The load side line voltage effective value Phase angle with load side line voltage .

[0018] When the line impedance is resistive, the effective value of the AC output line voltage of the converter of the i-th distributed energy generator DGi is measured. , line resistance R i The load side line voltage effective value .

[0019] Step 12: Measure the effective value of the inverter AC output line voltage , AC converter output line voltage phase angle measurement , load side line voltage effective value Phase angle with load side line voltage The data is fed back to the cluster optimal control module of the power grid dispatching center to obtain the active output reference value that each distributed energy generator needs to bear when the load changes. When the line impedance is inductive, the active output reference value is ; When the line impedance is resistive, the active output reference value is .

[0020] Step 2: Perform active output correction, including active output phase angle correction and active output voltage correction, which is achieved through the active output phase angle correction module and the active output voltage correction module; the active output phase angle correction module outputs the phase angle correction reference value based on the PMU data The active output voltage correction module outputs voltage correction reference value based on PMU data ,include:

[0021] Step 21: When multiple inverters are connected in parallel, the active output of each inverter for:

[0022] (1)

[0023] Where n is the total number of inverters connected in parallel, is the line impedance of the ith line, is the line impedance angle of the ith line, is the effective value of the AC output line voltage of the converter, is the phase angle of the voltage signal on the AC side of the converter, is the effective value of the load side line voltage, is the phase angle of the line voltage on the load side.

[0024] set up , j is an imaginary unit, indicating , is the line resistance, is the line reactance, which is substituted into formula (1) to obtain:

[0025] (2)

[0026] If the line impedance is inductive, the simplified active output of each converter is:

[0027] (3)

[0028] If the line impedance is resistive, the simplified active output of each converter is:

[0029] (4)

[0030] It can be seen from formula (3) that when the line impedance is inductive, the current output power of the distributed energy generator set is AC measurement of output line voltage RMS with converter , AC converter output line voltage phase angle measurement , load side line voltage effective value , load side line voltage phase angle and line reactance related.

[0031] If the grid dispatching center assigns a new active output reference value to the i-th distributed energy generator set, , then if we want to achieve the new public output reference value The corresponding active power-phase angle control should output a phase angle reference value of , as shown in formula (5):

[0032] (5)

[0033] It can be seen from formula (4) that when the line impedance is resistive, the current output power of the distributed energy generator set is AC measurement of output line voltage RMS with converter , load side line voltage effective value , load side line voltage phase angle With line resistance related.

[0034] If the grid dispatching center assigns a new active output reference value to the i-th distributed energy generator set , if we want to achieve the new active output reference value The corresponding active power-voltage control should output a voltage reference value of , as shown in formula (6):

[0035] (6)

[0036] Step 22: When the line impedance is inductive, enter the new active output reference value , the effective value of the inverter AC output line voltage measured by PMU , line reactance X i , load side line voltage effective value Phase angle with load side line voltage , calculated by formula (5) , which is to change the active output reference value to the new active output reference value After that, the new phase angle reference value corresponding to the new state of the i-th distributed energy generator set is .

[0037] New phase angle reference value Phase Angle Subtract the phase angle correction reference value output by the active output phase angle correction module. , which is shown in formula (7):

[0038] (7)

[0039] When the line impedance is resistive, enter the new active output reference value , the line resistance R measured by the PMU i The load side line voltage effective value , calculated by formula (6) , change the active output reference value to the new active output reference value After that, the new voltage reference value corresponding to the new state of the i-th distributed energy generator set is As shown in formula (8):

[0040] (8)

[0041] Step 3: Combine the active power droop control with the active power output correction module to make each distributed energy generator ignore the droop coefficient and output active power to any active power reference value. ; The active power droop control includes active power-phase angle droop control and active power-voltage droop control, and the active power output correction module is divided into an active power output phase angle correction module and an active power output voltage correction module; when the line impedance is inductive, the active power-phase angle droop control is combined with the active power output phase angle correction module; when the line impedance is resistive, the active power-voltage droop control is combined with the active power output voltage correction module; when the line impedance is inductive, the active power output reference value is ; When the line impedance is resistive, the active output reference value is ,include:

[0042] Step 31: When the line impedance is inductive:

[0043] It can be seen from formula (3) that when the line impedance is inductive, the active output of the converter is The inverter power angle (Converter power angle Measure the output line voltage phase angle of the inverter AC Phase angle with load side line voltage The difference is: ) into a linear function relationship (droop characteristic), based on which a control method based on the droop characteristic can be designed. The formula for active power-phase angle droop control is:

[0044] (9)

[0045] in, is the converter power angle reference value output by the active power-phase angle droop control of the i-th distributed energy generator set, is the converter power angle of the i-th distributed energy generator set when it is unloaded, is the active power-phase angle droop control droop coefficient of the i-th distributed energy generator set, It is the active output of each converter.

[0046] The active power output is distributed according to the active power-phase angle droop coefficient, as shown in formula (10):

[0047] (10)

[0048] Active power-phase angle droop control calculates and outputs the phase angle reference value according to formula (9) After that, the active output reference value The corresponding phase angle correction reference value is Add together to get the final phase angle reference value of the corresponding active power-phase angle droop grid control output , as shown in formula (11):

[0049] (11)

[0050] in, .

[0051] Final phase angle reference value Phase Angle Make a difference, and output the filter capacitor voltage angle through the PI controller , sent to the next control link.

[0052] When the line impedance is resistive:

[0053] It can be seen from formula (4) that when the line impedance is resistive, the active output of the converter is AC measurement of output line voltage RMS with converter It forms a linear function relationship (droop characteristic), based on which a control method based on the droop characteristic can be designed. The formula for active power-voltage droop control is:

[0054] (12)

[0055] in, is the reference value of the effective value of the AC output line voltage of the converter output of the i-th distributed energy generator set for active power-voltage droop control, is the effective value of the AC output line voltage of the converter when the i-th distributed energy generator set is unloaded, is the active-voltage droop control coefficient of the i-th distributed energy generator set, It is the active output of each converter.

[0056] The active power output is distributed according to the active power-voltage droop coefficient, as shown in formula (13):

[0057] (13)

[0058] Active power-voltage droop control calculates and outputs the phase angle reference value according to formula (12): After that, the active output reference value Corresponding phase angle correction reference value Add together to get the final voltage reference value of the corresponding active power-phase angle droop grid control output , as shown in formula (14):

[0059] (14)

[0060] in, .

[0061] and converter voltage Make a difference, and output the filter capacitor voltage through the PI controller , sent to the next control link.

[0062] Step 32: Filter Capacitor Voltage Angle and filter capacitor voltage After passing through the voltage and current dual closed-loop module and the pulse width modulation (PWM) module, the final PWM wave is transmitted to the converter gate to control the on and off of the converter switching device.

Claims

1. A PMU-based active networking control method for a high proportion of renewable energy clusters, characterized in that: The steps include: Step 1: The grid dispatching center allocates the active output P that each distributed energy generator should bear through cluster optimization control refi ; Step 2: Perform active output correction, including active output phase angle correction and active output voltage correction, which is achieved through the active output phase angle correction module and the active output voltage correction module; the active output phase angle correction module outputs the phase angle correction reference value based on the PMU data The active output voltage correction module outputs voltage correction reference value based on PMU data ; Step 3: Combine the active power droop control with the active power output correction module to make each distributed energy generator ignore the droop coefficient and output active power to any active power reference value. ; The active power droop control includes active power-phase angle droop control and active power-voltage droop control, and the active power output correction module is divided into an active power output phase angle correction module and an active power output voltage correction module; when the line impedance is inductive, the active power-phase angle droop control is combined with the active power output phase angle correction module; when the line impedance is resistive, the active power-voltage droop control is combined with the active power output voltage correction module; when the line impedance is inductive, the active power output reference value is ; When the line impedance is resistive, the active output reference value is ,include: Step 31: When the line impedance is inductive: according to When the line impedance is inductive, the active output of the converter The inverter power angle A linear function relationship is formed, and a control method based on the droop characteristic is designed accordingly. The formula for active power-phase angle droop control is: （9） in, is the converter power angle reference value output by the active power-phase angle droop control of the i-th distributed energy generator set, is the converter power angle of the i-th distributed energy generator set when it is unloaded, is the active power-phase angle droop control droop coefficient of the i-th distributed energy generator set, The active output of each converter; the active output is distributed according to the active-phase angle droop coefficient; Active power-phase angle droop control calculates and outputs the phase angle reference value according to formula (9) After that, the active output reference value The corresponding phase angle correction reference value is Add together to get the final phase angle reference value of the corresponding active power-phase angle droop grid control output , as shown in formula (11): （11） in, ; Final phase angle reference value Phase Angle Make a difference, and output the filter capacitor voltage angle through the PI controller , sent to the next control link; When the line impedance is resistive: according to When the line impedance is resistive, the active output of the converter is AC measurement of output line voltage RMS with converter A linear function relationship is formed, and a control method based on the droop characteristic is designed accordingly. The formula for active power-voltage droop control is: （12） in, is the reference value of the effective value of the AC output line voltage of the converter output of the i-th distributed energy generator set for active power-voltage droop control, is the effective value of the AC output line voltage of the converter when the i-th distributed energy generator set is unloaded, is the active-voltage droop control coefficient of the i-th distributed energy generator set, The active output of each converter; Active power output is distributed according to the active power-voltage droop coefficient; Active power-voltage droop control calculates and outputs the phase angle reference value according to formula (12): After that, the active output reference value Corresponding phase angle correction reference value Add together to get the final voltage reference value of the corresponding active power-phase angle droop grid control output , as shown in formula (14): （14） in, ; and converter voltage Make a difference, and output the filter capacitor voltage through the PI controller , sent to the next control link.

2. The active networking control method for high-proportion renewable energy clusters based on PMU according to claim 1 is characterized in that: The step 1 comprises: Step 11: Establish a PMU-based grid dispatch center new energy distributed generation wide-area measurement system to monitor the real-time data of each distributed energy generator set in real time; when the line impedance between the converter and the load is inductive, measure the effective value of the converter AC output line voltage of the i-th distributed energy generator set DGi And the inverter AC output line voltage phase angle , line reactance X i The load side line voltage effective value Phase angle with load side line voltage ; When the line impedance is resistive, the effective value of the AC output line voltage of the converter of the i-th distributed energy generator DGi is measured , line resistance R i The load side line voltage effective value ; Step 12: Measure the effective value of the inverter AC output line voltage , AC converter output line voltage phase angle measurement , load side line voltage effective value Phase angle with load side line voltage The data is fed back to the cluster optimal control module of the power grid dispatching center to obtain the active output reference value that each distributed energy generator needs to bear when the load changes. When the line impedance is inductive, the active output reference value is ; When the line impedance is resistive, the active output reference value is .

3. The active networking control method for high-proportion renewable energy clusters based on PMU according to claim 1 is characterized in that: The step 2 comprises: Step 21: When n inverters are connected in parallel, the active output of the i-th inverter Divided into and There are two situations, specifically: If the line impedance is inductive, the simplified active output of each converter is: （3） If the line impedance is resistive, the simplified active output of each converter is: （4） in, is the effective value of the AC output line voltage of the converter, is the phase angle of the voltage signal on the AC side of the converter, is the effective value of the line voltage on the load side, is the load side line voltage phase angle, is the line resistance, is the line reactance; .

4. The active networking control method for high-proportion renewable energy clusters based on PMU according to claim 3 is characterized in that: If the grid dispatching center assigns a new active output reference value to the i-th distributed energy generator set, , then if we want to achieve the new public output reference value The corresponding active power-phase angle control should output a phase angle reference value of , as shown in formula (5): （5）。 5. The active networking control method for high-proportion renewable energy clusters based on PMU according to claim 4 is characterized in that: If the grid dispatching center assigns a new active output reference value to the i-th distributed energy generator set , if we want to achieve the new active output reference value The corresponding active power-voltage control should output a voltage reference value of , as shown in formula (6): （6）。 6. The active networking control method for high-proportion renewable energy clusters based on PMU according to claim 5 is characterized in that: The step 2 comprises: Step 22: When the line impedance is inductive, enter the new active output reference value , the effective value of the inverter AC output line voltage measured by PMU , line reactance X i , load side line voltage effective value Phase angle with load side line voltage , calculated by formula (5) , which is to change the active output reference value to the new active output reference value After that, the new phase angle reference value corresponding to the new state of the i-th distributed energy generator set is ; New phase angle reference value Phase Angle Subtract the phase angle correction reference value output by the active output phase angle correction module. , which is shown in formula (7): （7） When the line impedance is resistive, enter the new active output reference value , the line resistance R measured by the PMU i The load side line voltage effective value , calculated by formula (6) , change the active output reference value to the new active output reference value After that, the new voltage reference value corresponding to the new state of the i-th distributed energy generator set is As shown in formula (8): （8）。 7. The active networking control method for high-proportion renewable energy clusters based on PMU according to claim 1 is characterized in that: The step 3 comprises: Filter capacitor voltage angle and filter capacitor voltage After passing through the voltage and current dual closed-loop module and the pulse width modulation module, the pulse width modulation wave is finally transmitted to the converter gate to control the on and off of the converter switching device.

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