Variable speed pumped storage unit control method and system based on dynamic target value

Abstract

The application discloses a variable-speed pumped storage unit control method based on a dynamic target value, which comprises the following steps: obtaining real-time operation parameters and unit parameters; calculating a frequency difference signal; calculating an input power reference quantity; calculating a basic rotating speed value and a basic opening value; calculating a rotating speed deviation control value and a stroke deviation control value; calculating a mechanical control quantity by PID control; and completing the control of a target variable-speed pumped storage unit according to the mechanical control quantity and an electromagnetic control quantity output by a converter. The application further discloses a system for realizing the variable-speed pumped storage unit control method based on the dynamic target value. The application is based on the dynamic target value, and is designed and realized by an innovative control algorithm, so that the variable-speed pumped storage unit control is completed, and the application has high reliability and good accuracy.

Description

Technical Field

[0001] This invention belongs to the field of hydropower unit control, specifically relating to a control method and system for variable speed pumped storage units based on dynamic target values. Background Technology

[0002] With the increasing prominence of environmental issues, new energy power generation systems have attracted worldwide attention due to their zero-emission and zero-pollution characteristics; more and more new energy power generation systems (mainly wind power generation systems and photovoltaic power generation systems) are also beginning to be connected to the power grid.

[0003] However, the energy sources of new energy power generation systems (wind for wind power systems and light for photovoltaic power systems) are highly random, making their output very unstable. Therefore, this random characteristic of new energy power generation systems exposes the power system to significant uncertainty. Consequently, the power system needs sufficient flexible regulation capacity and sufficiently rapid flexible control schemes to ensure its safe and stable operation.

[0004] Pumped storage power stations are an important component of the power system, playing crucial roles in peak shaving, frequency regulation, phase regulation, and backup power. Controlling pumped storage power stations is also considered one of the best solutions for addressing the output uncertainties of new energy power generation systems. Therefore, flexible control of pumped storage power stations is particularly important for the power system.

[0005] Currently, pumped storage power stations generally use traditional hydroelectric generators or constant-speed pumped storage units. These units suffer from a significant drop in efficiency when deviating from their design operating points. Variable-speed pumped storage units are an innovative technology developed in recent years; they offer advantages such as a wide operating range, a large adjustable power range, and high steady-state operating efficiency, making them the preferred choice for pumped storage power station units.

[0006] However, the control schemes for variable-speed pumped storage units cannot be applied to traditional hydroelectric units or constant-speed pumped storage units. Furthermore, my country currently lacks research on corresponding control schemes for variable-speed pumped storage units. This results in the absence of a complete and reliable control scheme for variable-speed pumped storage units in my country. Summary of the Invention

[0007] One of the objectives of this invention is to provide a highly reliable and accurate control method for variable speed pumped storage units based on dynamic target values.

[0008] The second objective of this invention is to provide a system for implementing the aforementioned control method for variable-speed pumped-storage units based on dynamic target values.

[0009] The variable-speed pumped-storage unit control method based on dynamic target values ​​provided by this invention includes the following steps:

[0010] S1. Obtain the real-time operating parameters and unit parameters of the target variable-speed pumped storage unit;

[0011] S2. Calculate the frequency difference signal based on the obtained real-time power grid frequency and power grid reference frequency;

[0012] S3. Calculate the input power reference value based on the frequency difference signal and the unit speed difference signal obtained in step S2;

[0013] S4. Based on the input power reference value obtained in step S3 and the comprehensive characteristic curve of the target variable speed pumped storage unit, calculate the basic speed value and the basic opening value.

[0014] S5. Calculate the speed deviation control value based on the basic speed value obtained in step S4, and calculate the stroke deviation control value based on the basic opening value obtained in step S4.

[0015] S6. Based on the speed deviation control value and stroke deviation control value obtained in step S5, the mechanical control quantity of the target variable speed pumped storage unit is calculated using the PID control algorithm.

[0016] S7. Based on the mechanical control quantity obtained in step S6 and the electromagnetic control quantity output by the converter of the target variable speed pumped storage unit, complete the control of the target variable speed pumped storage unit.

[0017] Step S2, which involves calculating the frequency difference signal based on the acquired real-time power grid frequency and the power grid reference frequency, specifically includes the following steps:

[0018] The calculated frequency difference signal Δf is as follows: Where Δf' is the frequency difference variable and Δf' = ff r f is the real-time frequency of the power grid. r This is the reference frequency for the power grid.

[0019] Step S3, which involves calculating the input power reference value based on the frequency difference signal obtained in step S2 and the unit's speed difference signal, specifically includes the following steps:

[0020] The input power reference quantity P is calculated using the following formula. i,r :

[0021] P i,r =P r -ΔP

[0022] In the formula P rThe target variable-speed pumped-storage unit's power setpoint; ΔP is the power correction value and e p Here, Δc is the power permanent state interpolation coefficient, and Δc = Δf + (n ref -n r ) / n r -x, Δf is the frequency difference signal, n ref n is the reference speed value for the target variable speed pumped storage unit. r Let x be the rated speed of the target variable speed pumped storage unit, and let x be the per-unit speed of the target variable speed pumped storage unit.

[0023] Step S4, which involves calculating the base speed and base opening value based on the input power reference obtained in step S3 and the comprehensive characteristic curve of the target variable speed pumped storage unit, specifically includes the following steps:

[0024] Based on the input power reference quantity P obtained in step S3 i,r Formulas for calculating the operating head H and power of the target variable speed pumped storage unit. The intermediate variable Q was calculated. 11 η, and then based on the comprehensive characteristic curve of the target variable speed pumped storage unit, the final base speed value n is calculated. p and basic opening value a p ;

[0025] Among them, P m Q is the target variable speed pumped storage unit's power. 11 η is an intermediate variable, γ is the specific weight of water, and D1 is the diameter of the turbine runner.

[0026] Step S5, which involves calculating the speed deviation control value based on the basic speed value obtained in step S4, and simultaneously calculating the stroke deviation control value based on the basic opening value obtained in step S4, specifically includes the following steps:

[0027] The speed deviation control value Δx is calculated using the following formula:

[0028]

[0029] In the formula n p The base rotational speed value obtained in step S4; H is the operating head of the target variable speed pumped storage unit; D1 is the turbine runner diameter; n r Let x be the rated speed of the target variable speed pumped storage unit, and let x be the per-unit speed of the target variable speed pumped storage unit.

[0030] The travel deviation control value Δy is calculated using the following formula:

[0031]

[0032] In the formula a p The basic opening value obtained in step S4; a max y represents the maximum opening value of the target variable speed pumped storage unit; y represents the current guide vane opening value of the turbine unit.

[0033] Step S6, which involves calculating the mechanical control quantities of the target variable-speed pumped-storage unit using a PID control algorithm based on the speed deviation control values ​​and stroke deviation control values ​​obtained in step S5, specifically includes the following steps:

[0034] The first PID control is applied to the speed deviation control value Δx to obtain the speed control quantity C. x The proportional coefficient of the first PID control is K. p1 The integral coefficient is K i1 The differential coefficient is K d1 The differential time coefficient is T i1 ;

[0035] The stroke deviation control value Δy is subjected to a second PID control to obtain the stroke control quantity C. y The proportional coefficient of the first PID control is K. p2 The integral coefficient is K i2 The differential coefficient is K d2 The differential time coefficient is T i2 ;

[0036] Finally, the speed control quantity C x and stroke control quantity C y By superimposing these values, the mechanical control quantities of the target variable-speed pumped storage unit are obtained.

[0037] This invention also discloses a system for implementing the aforementioned control method for a variable-speed pumped-storage unit based on dynamic target values, specifically including a parameter acquisition module, a frequency difference calculation module, a power parameter calculation module, a basic calculation module, a speed / stroke control module, a mechanical control module, and an output module; the parameter acquisition module, frequency difference calculation module, power parameter calculation module, basic calculation module, speed / stroke control module, mechanical control module, and output module are connected in series; the parameter acquisition module is used to acquire the real-time operating parameters and unit parameters of the target variable-speed pumped-storage unit and upload the data to the frequency difference calculation module; the frequency difference calculation module is used to calculate the frequency difference signal based on the acquired data and upload the data to the power parameter calculation module; the power parameter calculation module is used to calculate the frequency difference signal based on the acquired data and upload the data to the power parameter calculation module; the power parameter calculation module is used to calculate the frequency difference signal based on the acquired data and upload the data to the power parameter calculation module; the power parameter calculation module is used to calculate the frequency difference signal based on the acquired data and upload the data to the power parameter calculation module. Based on the acquired data, the input power reference value is calculated and uploaded to the basic calculation module. The basic calculation module calculates the basic speed value and basic opening value based on the acquired data and uploads the data to the stroke control module. The speed / stroke control module calculates the speed deviation control value and stroke deviation control value based on the acquired data and uploads the data to the mechanical control module. The mechanical control module calculates the mechanical control quantity of the target variable speed pumped storage unit using a PID control algorithm based on the acquired data and uploads the data to the output module. The output module completes the control of the target variable speed pumped storage unit based on the acquired data and the electromagnetic control quantity output by the converter of the target variable speed pumped storage unit.

[0038] The variable speed pumped storage unit control method and system based on dynamic target values ​​provided by this invention, through innovative control algorithm design and implementation, not only completes the control of the variable speed pumped storage unit, but also has high reliability and good accuracy. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0040] Figure 2 This is a schematic diagram of the per-unit speed curve when the network frequency suddenly increases by 0.1Hz according to the method of the present invention.

[0041] Figure 3 This is a schematic diagram of the relay travel curve for a sudden increase in network frequency of 0.1Hz in the method of the present invention.

[0042] Figure 4 The P value is ±0.1Hz of the network frequency change in the method of the present invention. 11 -n 11 A schematic diagram of the migration curve.

[0043] Figure 5 This is a schematic diagram of the system functional modules of the present invention. Detailed Implementation

[0044] like Figure 1 The diagram shown is a flowchart of the method of the present invention: The variable speed pumped storage unit control method based on dynamic target values ​​provided by the present invention includes the following steps:

[0045] S1. Obtain the real-time operating parameters and unit parameters of the target variable-speed pumped storage unit;

[0046] S2. Calculate the frequency difference signal based on the acquired real-time power grid frequency and power grid reference frequency; specifically including the following steps:

[0047] The calculated frequency difference signal Δf is as follows: Where Δf' is the frequency difference variable and Δf' = ff r f is the real-time frequency of the power grid. r This is the power grid reference frequency;

[0048] S3. Based on the frequency difference signal and the unit speed difference signal obtained in step S2, calculate the input power reference value; specifically including the following steps:

[0049] The input power reference quantity P is calculated using the following formula. i,r :

[0050] P i,r =P r -ΔP

[0051] In the formula P r The target variable-speed pumped-storage unit's power setpoint; ΔP is the power correction value and e p Here, Δc is the power permanent state interpolation coefficient, and Δc = Δf + (n ref -n r ) / n r -x, Δf is the frequency difference signal, n ref n is the reference speed value for the target variable speed pumped storage unit. r Let x be the rated speed of the target variable speed pumped storage unit, and let x be the per-unit speed of the target variable speed pumped storage unit.

[0052] S4. Based on the input power reference obtained in step S3 and the comprehensive characteristic curve of the target variable speed pumped storage unit, calculate the base speed value and base opening value; specifically including the following steps:

[0053] Based on the input power reference quantity P obtained in step S3 i,r Formulas for calculating the operating head H and power of the target variable speed pumped storage unit. The intermediate variable Q was calculated. 11η, and then based on the comprehensive characteristic curve of the target variable speed pumped storage unit, the final base speed value n is calculated. p and basic opening value a p ;

[0054] Among them, P m Q is the target variable speed pumped storage unit's power. 11 η is an intermediate variable, γ is the specific weight of water, and D1 is the diameter of the turbine runner;

[0055] S5. Calculate the speed deviation control value based on the basic speed value obtained in step S4, and simultaneously calculate the stroke deviation control value based on the basic opening value obtained in step S4; specifically including the following steps:

[0056] The speed deviation control value Δx is calculated using the following formula:

[0057]

[0058] In the formula n p The base rotational speed value obtained in step S4; H is the operating head of the target variable speed pumped storage unit; D1 is the turbine runner diameter; n r Let x be the rated speed of the target variable speed pumped storage unit, and let x be the per-unit speed of the target variable speed pumped storage unit.

[0059] The travel deviation control value Δy is calculated using the following formula:

[0060]

[0061] In the formula a p The basic opening value obtained in step S4; a max y represents the maximum opening value of the target variable speed pumped storage unit; y represents the current guide vane opening value of the turbine unit.

[0062] S6. Based on the speed deviation control value and stroke deviation control value obtained in step S5, the mechanical control quantity of the target variable speed pumped storage unit is calculated using a PID control algorithm; specifically, the following steps are included:

[0063] The first PID control is applied to the speed deviation control value Δx to obtain the speed control quantity C. x The proportional coefficient of the first PID control is K. p1 The integral coefficient is K i1 The differential coefficient is K d1 The differential time coefficient is T i1 ;

[0064] The stroke deviation control value Δy is subjected to a second PID control to obtain the stroke control quantity C. yThe proportional coefficient of the first PID control is K. p2 The integral coefficient is K i2 The differential coefficient is K d2 The differential time coefficient is T i2 ;

[0065] Finally, the speed control quantity C x and stroke control quantity C y By superimposing these values, the mechanical control quantities of the target variable-speed pumped storage unit are obtained.

[0066] S7. Based on the mechanical control quantity obtained in step S6 and the electromagnetic control quantity output by the converter of the target variable-speed pumped storage unit, the control of the target variable-speed pumped storage unit is completed. In specific implementation, the mechanical control quantity obtained in step S6 is input into the mechanical-hydraulic control system of the target variable-speed pumped storage unit to realize the control of the mechanical-hydraulic control system, and then the target variable-speed pumped storage unit is controlled by the output of the mechanical-hydraulic control system. At the same time, the electromagnetic control quantity output by the converter of the target variable-speed pumped storage unit is directly output to the target variable-speed pumped storage unit to realize the control of the target variable-speed pumped storage unit.

[0067] In the method of this invention, the input power reference quantity P mrefp Based on the target power reference value P mref The power deviation correction value, which includes both the primary frequency regulation deviation and the speed deviation, enables the measured speed and measured servo travel to promptly follow the target speed and target servo travel during the dynamic adjustment of the primary frequency regulation. This method is applicable to any type of turbine. The speed and opening curves after simulating a 0.1Hz grid frequency disturbance are shown below. Figure 2 and Figure 3 As shown;

[0068] Figure 4 Method 2 in the present invention describes the migration trajectory of unit power P11 - unit speed n11 during the primary frequency regulation dynamic adjustment process. Method 3 describes the migration trajectory of unit power P11 - unit speed n11 during the primary frequency regulation dynamic adjustment process of a variable speed pumped storage unit based on a fixed relay stroke. Method 1 describes the migration trajectory of unit power P11 - unit speed n11 during the primary frequency regulation dynamic adjustment process of a variable speed unit based on power setpoint correction and the system.

[0069] pass Figures 2-4 As can be seen, the method of the present invention has a good control effect.

[0070] like Figure 5The diagram shows the system functional modules of the present invention: The system provided by the present invention for implementing the above-mentioned control method for variable speed pumped storage units based on dynamic target values ​​specifically includes a parameter acquisition module, a frequency difference calculation module, a power parameter calculation module, a basic calculation module, a speed / stroke control module, a mechanical control module, and an output module; the parameter acquisition module, frequency difference calculation module, power parameter calculation module, basic calculation module, speed / stroke control module, mechanical control module, and output module are connected in series; the parameter acquisition module is used to acquire the real-time operating parameters and unit parameters of the target variable speed pumped storage unit and upload the data to the frequency difference calculation module; the frequency difference calculation module is used to calculate the frequency difference signal based on the acquired data and upload the data to the power parameter calculation module; The power parameter calculation module calculates the input power reference value based on the acquired data and uploads the data to the basic calculation module. The basic calculation module calculates the basic speed value and basic opening value based on the acquired data and uploads the data to the stroke control module. The speed / stroke control module calculates the speed deviation control value and stroke deviation control value based on the acquired data and uploads the data to the mechanical control module. The mechanical control module calculates the mechanical control quantity of the target variable speed pumped storage unit using a PID control algorithm based on the acquired data and uploads the data to the output module. The output module completes the control of the target variable speed pumped storage unit based on the acquired data and the electromagnetic control quantity output by the converter of the target variable speed pumped storage unit.

[0071] The control process of this invention is very rapid, capable of completing adjustment and control within milliseconds; moreover, the control process of this invention operates entirely within the turbine's highest efficiency range, resulting in high steady-state operating efficiency and good unit stability; this invention simultaneously employs speed and opening degree regulation of the turbine output, offering the advantage of rapid turbine output regulation on the prime mover side; furthermore, this invention enables the primary frequency regulation steady-state load to be less than 40% of the unit's rated load, achieving rapid and significant load increase under low load conditions; finally, this invention can maintain safe and stable unit operation even when the opening degree signal disappears, demonstrating high fault tolerance in the control method.

Claims

1. A control method for a variable-speed pumped-storage unit based on dynamic target values, comprising the following steps: S1. Obtain the real-time operating parameters and unit parameters of the target variable-speed pumped storage unit; S2. Based on the acquired real-time power grid frequency and power grid reference frequency, the frequency difference signal is calculated; specifically, the following steps are included: The frequency difference signal was calculated. for ,in It is a frequency difference variable and , For the real-time frequency of the power grid, This is the power grid reference frequency; S3. Based on the frequency difference signal and the unit speed difference signal obtained in step S2, calculate the input power reference value; specifically including the following steps: The input power reference value is calculated using the following formula. : In the formula The power setpoint for the target variable speed pumped storage unit; Power correction value and , These are the power permanent interpolation coefficients. The comprehensive deviation value and , It is a frequency difference signal. The reference speed value for the target variable speed pumped storage unit. The target variable speed pumped storage unit's rated speed. The per-unit value of the target variable-speed pumped storage unit; S4. Based on the input power reference value obtained in step S3 and the comprehensive characteristic curve of the target variable speed pumped storage unit, calculate the basic speed value and basic opening value; specifically including the following steps: Based on the input power reference obtained in step S3 The target variable speed pumped storage unit's operating head Power calculation formula for target variable speed pumped storage unit The intermediate variables were calculated. Then, based on the comprehensive characteristic curve of the target variable speed pumped storage unit, the final base speed value is calculated. and basic opening value ; in, The target is the power output of the variable speed pumped storage unit. As an intermediate variable, The density of water, The diameter of the turbine runner; S5. Calculate the speed deviation control value based on the basic speed value obtained in step S4, and simultaneously calculate the stroke deviation control value based on the basic opening value obtained in step S4; specifically including the following steps: The speed deviation control value is calculated using the following formula. : In the formula The base rotational speed value obtained in step S4; The target is the operating head of the variable speed pumped storage unit; The diameter of the turbine runner; The target variable speed pumped storage unit's rated speed. The per-unit value of the target variable-speed pumped storage unit; The travel deviation control value is calculated using the following formula. : In the formula The basic opening value obtained in step S4; The maximum opening value of the target variable speed pumped storage unit; This represents the current guide vane opening value of the turbine unit; S6. Based on the speed deviation control value and stroke deviation control value obtained in step S5, the mechanical control quantity of the target variable speed pumped storage unit is calculated using a PID control algorithm; specifically, the following steps are included: Speed ​​deviation control value Perform the first PID control to obtain the speed control quantity. The proportional coefficient of the first PID control is The integral coefficient is The differential coefficient is The differential time coefficient is ; travel deviation control value Perform a second PID control to obtain the stroke control quantity. The proportional coefficient of the first PID control is The integral coefficient is The differential coefficient is The differential time coefficient is ; Finally, the speed control quantity and stroke control quantity By superimposing these values, the mechanical control quantities of the target variable-speed pumped storage unit are obtained. S7. Based on the mechanical control quantity obtained in step S6 and the electromagnetic control quantity output by the converter of the target variable speed pumped storage unit, complete the control of the target variable speed pumped storage unit.

2. A system for implementing the variable speed pumped storage unit control method based on dynamic target values ​​as described in claim 1, characterized in that... Specifically, it includes a parameter acquisition module, a frequency difference calculation module, a power parameter calculation module, a basic calculation module, a speed / stroke control module, a mechanical control module, and an output module; these modules are connected in series. The parameter acquisition module acquires the real-time operating parameters and unit parameters of the target variable speed pumped storage unit and uploads the data to the frequency difference calculation module. The frequency difference calculation module calculates the frequency difference signal based on the acquired data and uploads the data to the power parameter calculation module. The power parameter calculation module calculates the input power reference value based on the acquired data and uploads the data to the basic calculation module; the basic calculation module calculates the basic speed value and basic opening value based on the acquired data and uploads the data to the stroke control module; the speed / stroke control module calculates the speed deviation control value and stroke deviation control value based on the acquired data and uploads the data to the mechanical control module; the mechanical control module calculates the mechanical control quantity of the target variable speed pumped storage unit using a PID control algorithm based on the acquired data and uploads the data to the output module. The output module is used to control the target variable speed pumped storage unit based on the acquired data and the electromagnetic control quantity output by the converter of the target variable speed pumped storage unit.

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