Variable speed unit primary frequency modulation method and system based on power setting correction

Abstract

The application discloses a variable-speed unit primary frequency modulation method based on power setting value correction, which comprises the following steps: obtaining real-time operation parameters of a target variable-speed unit; a converter of the target variable-speed unit calculates an electromagnetic power variation corresponding to a primary frequency modulation action; a control amount of a mechanical hydraulic system of the target variable-speed unit is calculated and input into the mechanical hydraulic system to obtain a mechanical hydraulic control amount; and the primary frequency modulation of the variable-speed unit is completed according to the electromagnetic power variation and the mechanical hydraulic control amount. The application further provides a system for implementing the variable-speed unit primary frequency modulation method based on power setting value correction. The variable-speed unit primary frequency modulation method and system based on power setting value correction provided by the application not only realize the primary frequency modulation of the variable-speed unit, but also have the advantages of fast frequency modulation speed, high reliability, good practicability and good frequency modulation effect by virtue of the innovative control strategy design.

Description

Technical Field

[0001] This invention belongs to the field of electrical automation, and specifically relates to a method and system for primary frequency regulation of variable speed generator units based on power setpoint correction. 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, with the large-scale grid connection of new energy power generation systems, the demand for flexible and adjustable regulation resources in the power system is increasing. Traditional hydropower units and constant-speed pumped storage units are difficult to operate below 40% of rated load due to factors such as vibration zones and pressure pulsations. After the units deviate from their design operating points, they suffer from problems such as a significant decrease in efficiency.

[0004] Variable-speed pumped-storage hydropower units possess advantages such as a wide operating range, a large adjustable power output, and high operating efficiency under steady-state conditions, offering potential advantages in improving power system flexibility and absorbing large-scale renewable energy sources. The primary frequency regulation method for variable-speed pumped-storage hydropower units differs significantly from that of traditional hydropower units and traditional constant-speed pumped-storage units, and currently, there is a lack of research in China on corresponding primary frequency regulation methods for variable-speed units. Summary of the Invention

[0005] One of the objectives of this invention is to provide a primary frequency regulation method for variable speed generators based on power setpoint correction, which is highly reliable, practical, and has good frequency regulation effect.

[0006] The second objective of this invention is to provide a system for implementing the aforementioned method for primary frequency regulation of variable speed generator units based on power setpoint correction.

[0007] The variable speed generator primary frequency regulation method based on power setpoint correction provided by this invention includes the following steps:

[0008] S1. Obtain the real-time operating parameters of the target variable speed unit;

[0009] S2. The converter of the target variable speed unit calculates the change in electromagnetic power corresponding to a single frequency regulation action based on the target electromagnetic power;

[0010] S3. Based on the change in grid frequency and the real-time operating parameters of the target variable speed unit, calculate the control quantity of the mechanical hydraulic system of the target variable speed unit, and input it into the mechanical hydraulic system to obtain the mechanical hydraulic control quantity;

[0011] S4. Based on the electromagnetic power change obtained in step S2 and the mechanical-hydraulic control quantity obtained in step S3, complete the first frequency adjustment of the variable speed unit.

[0012] Step S3, which involves calculating the control quantities of the mechanical-hydraulic system of the target variable-speed generator unit based on the changes in the power grid frequency and the real-time operating parameters of the target variable-speed generator unit, specifically includes the following steps:

[0013] A. Obtain the actual frequency and reference frequency of the power grid, and obtain the power correction amount caused by a frequency modulation action through an artificial frequency dead zone unit;

[0014] B. Based on the power correction amount and target electromagnetic power obtained in step A, calculate the target power input to the optimal efficiency tracking unit after considering the primary frequency modulation function;

[0015] C. Based on the target power and the turbine comprehensive characteristic curve of the target variable speed unit obtained in step B, calculate the target unit speed and the target guide vane opening.

[0016] D. Calculate the target unit speed based on the target unit speed obtained in step C and the actual operating head of the target variable speed unit;

[0017] E. Based on the target unit speed, rated unit speed, and per-unit speed of the target variable speed unit obtained in step D, the target speed error signal is calculated;

[0018] F. Based on the target guide vane opening, the maximum guide vane opening of the target variable speed unit, and the per-unit value of the relay stroke of the target variable speed unit obtained in step C, calculate the target opening error signal;

[0019] G. Based on the target speed error signal obtained in step E and the target opening error signal obtained in step F, calculate the control quantity of the mechanical hydraulic system of the target variable speed unit.

[0020] Step A, which involves obtaining the actual frequency and reference frequency of the power grid and then using an artificial frequency dead zone unit to obtain the power correction caused by a single frequency modulation operation, specifically includes the following steps:

[0021] Obtain the actual frequency f and the reference frequency f of the power grid. ref ;

[0022] Setting the artificial frequency dead zone unit E f for

[0023] The power correction ΔP caused by a single frequency modulation operation is calculated. mref for Where e pThese are the power permanent state interpolation coefficients.

[0024] Step B, which involves calculating the target power input to the optimal efficiency tracking unit considering the primary frequency modulation function based on the power correction amount and target electromagnetic power obtained in step A, specifically includes the following steps:

[0025] The target power P of the optimal efficiency tracking unit input, considering the primary frequency modulation function, is calculated. mrefp For P mrefp =P mref -ΔP mref , where P mref For the target electromagnetic power, ΔP mref This is the power correction amount obtained in step A.

[0026] Step C, which involves calculating the target unit speed and target guide vane opening based on the target power and the turbine comprehensive characteristic curve of the target variable speed unit obtained in step B, specifically includes the following steps:

[0027] Based on the target power P obtained in step B mrefp The formulas for calculating the actual operating head H and turbine power P of the target variable speed unit. m =γD1 2 H 3 / 2 Q 11 η, calculate the combined variable Q 11 η, and then based on the comprehensive characteristic curve of the turbine of the target variable speed unit. Calculate the target unit speed and target guide vane opening a * ;

[0028] Among them, P m Where γ is the power of the turbine, γ is the specific gravity of water, D1 is the diameter of the turbine runner, and Q is the specific gravity of the turbine. 11 Let η be the unit flow rate of the turbine, η be the efficiency of the turbine, a be the guide vane opening of the turbine, and n be the flow rate of the turbine. 11 This represents the unit rotational speed of the water turbine.

[0029] Step D, which involves calculating the target unit speed based on the target unit speed obtained in step C and the actual operating head of the target variable speed unit, specifically includes the following steps:

[0030] Based on the target unit rotation speed obtained in step C The target unit speed n is calculated from the actual operating head H of the target variable speed unit. ref for Where D1 is the diameter of the turbine runner.

[0031] Step E, which involves calculating the target speed error signal based on the target unit speed, rated unit speed, and per-unit speed value of the target variable speed unit obtained in step D, specifically includes the following steps:

[0032] Based on the target unit speed n obtained in step D ref Rated speed of the unit n r The target speed error signal e is calculated from the per-unit speed value x of the target variable speed unit. n for

[0033] Step F, which involves calculating the target guide vane opening, the maximum guide vane opening of the target variable speed unit, and the per-unit value of the relay stroke of the target variable speed unit obtained in step C, specifically includes the following steps:

[0034] Based on the target guide vane opening a obtained in step C * The maximum guide vane opening a of the target variable speed unit max The target opening error signal e is calculated from the per-unit value y of the relay stroke of the target variable speed unit. y for

[0035]

[0036] Step G, which involves calculating the control quantity of the mechanical-hydraulic system of the target variable speed unit based on the target speed error signal obtained in step E and the target opening error signal obtained in step F, specifically includes the following steps:

[0037] Based on the target speed error signal e obtained in step E n The target opening error signal e obtained in step F y The control quantity y of the mechanical-hydraulic system of the target variable speed unit is calculated using the following formula. PID :

[0038]

[0039] In the formula K p1 K is the proportional coefficient of the speed error signal; i1 K represents the integral coefficient of the rotational speed error signal. d1 T is the differential time coefficient of the rotational speed error signal; 1v1 K represents the time constant of the actual differential element of the rotational speed error signal. p2 K is the proportional coefficient of the opening error signal; i2 K represents the integral coefficient of the opening error signal. d2 T is the differential time coefficient of the opening error signal; 1v2 The time constant of the actual differential element of the opening error signal is denoted as .

[0040] This invention also discloses a system for implementing the aforementioned method for primary frequency regulation of a variable speed generator based on power setpoint correction. Specifically, it includes a parameter acquisition module, an electromagnetic power change calculation module, a mechanical-hydraulic control quantity calculation module, and a primary frequency regulation module. The output of the parameter acquisition module is connected to the inputs of the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module. The outputs of the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module are connected to the input of the primary frequency regulation module. The output of the primary frequency regulation module is connected to the target variable speed generator. The parameter acquisition module is used to acquire the real-time operating parameters of the target variable speed generator, and... The data is uploaded to the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module. The electromagnetic power change calculation module calculates the electromagnetic power change corresponding to the primary frequency regulation action based on the acquired parameter information and outputs it to the primary frequency regulation module. The mechanical-hydraulic control quantity calculation module calculates the control quantity of the mechanical-hydraulic system of the target variable speed unit based on the acquired parameter information, inputs it into the mechanical-hydraulic system to obtain the mechanical-hydraulic control quantity, and outputs the mechanical-hydraulic control quantity to the primary frequency regulation module. The primary frequency regulation module completes the primary frequency regulation of the variable speed unit based on the received electromagnetic power change and mechanical-hydraulic control quantity.

[0041] The method and system for primary frequency regulation of variable speed generator units based on power setpoint correction provided by this invention, through innovative control strategy design, not only realizes primary frequency regulation of variable speed generator units, but also has fast frequency regulation speed, high reliability, good practicality and good frequency regulation effect. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0043] 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.

[0044] 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.

[0045] Figure 4 The P value is ±0.1Hz of the network frequency change in the method of this invention. 11 -n 11 A schematic diagram of the migration curve.

[0046] Figure 5 This is a schematic diagram of the system functional modules of the present invention. Detailed Implementation

[0047] like Figure 1The diagram shown is a flowchart of the method of the present invention: The variable speed unit primary frequency regulation method based on power setpoint correction provided by the present invention includes the following steps:

[0048] S1. Obtain the real-time operating parameters of the target variable speed unit (target variable speed pumped storage hydropower unit);

[0049] S2. The converter of the target variable speed unit calculates the change in electromagnetic power corresponding to a single frequency regulation action based on the target electromagnetic power;

[0050] S3. Based on the changes in the power grid frequency and the real-time operating parameters of the target variable speed unit, calculate the control quantity of the mechanical-hydraulic system of the target variable speed unit, and input it into the mechanical-hydraulic system to obtain the mechanical-hydraulic control quantity; specifically including the following steps:

[0051] A. Obtain the actual frequency and reference frequency of the power grid, and obtain the power correction amount caused by the first frequency regulation action through an artificial frequency dead zone unit; specifically including the following steps:

[0052] Obtain the actual frequency f and the reference frequency f of the power grid. ref ;

[0053] Setting the artificial frequency dead zone unit E f for

[0054] The power correction ΔP caused by a single frequency modulation operation is calculated. mref for Where e p These are the power permanent state interpolation coefficients;

[0055] B. Based on the power correction amount and target electromagnetic power obtained in step A, calculate the target power input to the optimal efficiency tracking unit after considering the primary frequency modulation function; specifically including the following steps:

[0056] The target power P of the optimal efficiency tracking unit input, considering the primary frequency modulation function, is calculated. mrefp For P mrefp =P mref -ΔP mref , where P mref For the target electromagnetic power, ΔP mref The power correction amount obtained in step A;

[0057] C. Based on the target power and the turbine comprehensive characteristic curve of the target variable speed unit obtained in step B, calculate the target unit speed and target guide vane opening; specifically including the following steps:

[0058] Based on the target power P obtained in step B mrefpThe formulas for calculating the actual operating head H and turbine power P of the target variable speed unit. m =γD1 2 H 3 / 2 Q 11 η, calculate the combined variable Q 11 η, and then based on the comprehensive characteristic curve of the turbine of the target variable speed unit. Calculate the target unit speed and target guide vane opening a * ;

[0059] Among them, P m Where γ is the power of the turbine, γ is the specific gravity of water, D1 is the diameter of the turbine runner, and Q is the specific gravity of the turbine. 11 Let η be the unit flow rate of the turbine, η be the efficiency of the turbine, a be the guide vane opening of the turbine, and n be the flow rate of the turbine. 11 The unit speed of the water turbine;

[0060] D. Based on the target unit speed obtained in step C and the actual operating head of the target variable speed unit, the target unit speed is calculated; specifically, the following steps are included:

[0061] Based on the target unit rotation speed obtained in step C The target unit speed n is calculated from the actual operating head H of the target variable speed unit. ref for Where D1 is the diameter of the turbine runner;

[0062] E. Based on the target unit speed, rated unit speed, and per-unit speed value of the target variable speed unit obtained in step D, the target speed error signal is calculated; specifically, the following steps are included:

[0063] Based on the target unit speed n obtained in step D ref Rated speed of the unit n r The target speed error signal e is calculated from the per-unit speed value x of the target variable speed unit. n for

[0064] F. Based on the target guide vane opening, the maximum guide vane opening of the target variable speed unit, and the per-unit value of the relay stroke of the target variable speed unit obtained in step C, the target opening error signal is calculated; specifically, the following steps are included:

[0065] Based on the target guide vane opening a obtained in step C * The maximum guide vane opening a of the target variable speed unit max The target opening error signal e is calculated from the per-unit value y of the relay stroke of the target variable speed unit. y for

[0066]

[0067] G. Based on the target speed error signal obtained in step E and the target opening error signal obtained in step F, calculate the control quantity of the mechanical-hydraulic system of the target variable speed unit; specifically including the following steps:

[0068] Based on the target speed error signal e obtained in step E n The target opening error signal e obtained in step F y The control quantity y of the mechanical-hydraulic system of the target variable speed unit is calculated using the following formula. PID :

[0069]

[0070] In the formula K p1 K is the proportional coefficient of the speed error signal; i1 K represents the integral coefficient of the rotational speed error signal. d1 T is the differential time coefficient of the rotational speed error signal; 1v1 K represents the time constant of the actual differential element of the rotational speed error signal. p2 K is the proportional coefficient of the opening error signal; i2 K represents the integral coefficient of the opening error signal. d2 T is the differential time coefficient of the opening error signal; 1v2 The actual differential element time constant of the opening error signal;

[0071] S4. Based on the electromagnetic power change obtained in step S2 and the mechanical-hydraulic control quantity obtained in step S3, complete the first frequency adjustment of the variable speed unit.

[0072] In the method of this invention, the power correction amount ΔP caused by a single frequency modulation operation mref (Corrected target power value P) mrefp The frequency modulation change is converted into a power action quantity;

[0073] The target rotational speed, target relay stroke, measured rotational speed, and actual relay stroke during a single frequency modulation process according to the method of this invention are as follows: Figures 2-4 As shown;

[0074] Figure 4Method 1 describes the primary frequency regulation method for variable speed pumped storage units based on power setpoint correction and the migration trajectory of unit power P11 - unit speed n11 during the dynamic adjustment of the primary frequency regulation process. Method 2 describes the control method for variable speed pumped storage units based on dynamic target values ​​and the migration trajectory of unit power P11 - unit speed n11 during the dynamic adjustment of the primary frequency regulation process. Method 3 describes the primary frequency regulation method for variable speed pumped storage units based on fixed servo travel and the migration trajectory of unit power P11 - unit speed n11 during the dynamic adjustment of the primary frequency regulation process.

[0075] pass Figures 2-4 As can be seen, the method of the present invention has a good control effect.

[0076] like Figure 5 The diagram shows the system functional modules of the present invention: The system disclosed in this invention for implementing the primary frequency regulation method of a variable speed generator based on power setpoint correction specifically includes a parameter acquisition module, an electromagnetic power change calculation module, a mechanical-hydraulic control quantity calculation module, and a primary frequency regulation module. The output of the parameter acquisition module is connected to the inputs of the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module. The outputs of the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module are connected to the input of the primary frequency regulation module. The output of the primary frequency regulation module is connected to the target variable speed generator. The parameter acquisition module is used to acquire the target variable speed generator. The system receives real-time operating parameters and uploads the data to the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module. The electromagnetic power change calculation module calculates the electromagnetic power change corresponding to the primary frequency modulation action based on the acquired parameter information and outputs it to the primary frequency modulation module. The mechanical-hydraulic control quantity calculation module calculates the control quantity of the mechanical-hydraulic system of the target variable speed unit based on the acquired parameter information, inputs it into the mechanical-hydraulic system to obtain the mechanical-hydraulic control quantity, and outputs the mechanical-hydraulic control quantity to the primary frequency modulation module. The primary frequency modulation module completes the primary frequency modulation of the variable speed unit based on the received electromagnetic power change and mechanical-hydraulic control quantity.

[0077] The variable speed turbine primary frequency regulation method and system based on power setpoint correction provided by this invention features rapid electromagnetic power response during primary frequency regulation, completing electromagnetic power adjustment within milliseconds. The turbine operates at its highest efficiency line during both the initial and final stages of primary frequency regulation, exhibiting high steady-state operating efficiency and good unit stability. Simultaneous adjustment of turbine output using both speed and turbine opening during the primary frequency regulation response provides the advantage of rapid turbine output adjustment on the prime mover side. 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 increases under low load conditions. Furthermore, the control strategy of this invention simultaneously utilizes speed and turbine opening errors, maintaining safe and stable unit operation even when the turbine opening signal disappears, demonstrating high fault tolerance in the primary frequency regulation control strategy.

Claims

1. A method for primary frequency regulation of a variable speed generator unit based on power setpoint correction, comprising the following steps: S1. Obtain the real-time operating parameters of the target variable speed unit; S2. The converter of the target variable speed unit calculates the change in electromagnetic power corresponding to a single frequency regulation action based on the target electromagnetic power; S3. Based on the changes in grid frequency and the real-time operating parameters of the target variable-speed generator unit, calculate the control quantities of the mechanical-hydraulic system of the target variable-speed generator unit, and input them into the mechanical-hydraulic system to obtain the mechanical-hydraulic control quantities; specifically including the following steps: A. Obtain the actual frequency and reference frequency of the power grid, and obtain the power correction amount caused by the first frequency regulation action through an artificial frequency dead zone unit; specifically including the following steps: Obtain the actual frequency of the power grid and the reference frequency of the power grid ; Setting artificial frequency dead zone unit for ; The power correction amount caused by a single frequency modulation operation is calculated. for ,in These are the power permanent state interpolation coefficients; B. Based on the power correction amount and target electromagnetic power obtained in step A, calculate the target power input to the optimal efficiency tracking unit after considering the primary frequency modulation function; specifically including the following steps: The target power of the optimal efficiency tracking unit input, considering the primary frequency modulation function, is calculated. for ,in For the target electromagnetic power, The power correction amount obtained in step A; C. Based on the target power and the turbine comprehensive characteristic curve of the target variable speed unit obtained in step B, calculate the target unit speed and target guide vane opening; specifically including the following steps: Based on the target power obtained in step B Actual operating head of the target variable speed unit Power calculation formula for water turbine The combined variables were calculated. Then, based on the comprehensive characteristic curve of the turbine of the target variable speed unit... The target unit rotational speed is calculated. and target guide vane opening ; in, The power of the water turbine. The density of water, The diameter of the turbine runner. The unit flow rate of the water turbine, For the efficiency of the water turbine, The guide vane opening of the water turbine. The unit speed of the water turbine; D. Based on the target unit speed obtained in step C and the actual operating head of the target variable speed unit, the target unit speed is calculated; specifically, the following steps are included: Based on the target unit rotation speed obtained in step C and the actual operating head of the target variable speed unit The target unit speed was calculated. for ,in The diameter of the turbine runner; E. Based on the target unit speed, rated unit speed, and per-unit speed value of the target variable speed unit obtained in step D, the target speed error signal is calculated; specifically, the following steps are included: Based on the target unit speed obtained in step D Rated speed of the unit per-unit speed of the target variable speed unit The target rotational speed error signal is calculated. for ; F. Based on the target guide vane opening, the maximum guide vane opening of the target variable speed unit, and the per-unit value of the relay stroke of the target variable speed unit obtained in step C, the target opening error signal is calculated; specifically, the following steps are included: Based on the target guide vane opening obtained in step C The maximum guide vane opening of the target variable speed unit Per-unit stroke of the relay unit of the target variable speed unit The target opening error signal is calculated. for ; G. Based on the target speed error signal obtained in step E and the target opening error signal obtained in step F, calculate the control quantity of the mechanical-hydraulic system of the target variable speed unit; specifically including the following steps: Based on the target speed error signal obtained in step E The target opening error signal obtained in step F The control quantity of the mechanical-hydraulic system of the target variable speed unit is calculated using the following formula. : In the formula This is the proportional coefficient of the speed error signal; The integral coefficient of the rotational speed error signal; The time coefficient of the differential speed error signal; The actual differential element time constant of the rotational speed error signal; This is the proportional coefficient of the opening error signal; The integral coefficient of the opening error signal; The differential time coefficient of the opening error signal; The actual differential element time constant of the opening error signal; S4. Based on the electromagnetic power change obtained in step S2 and the mechanical-hydraulic control quantity obtained in step S3, complete the first frequency adjustment of the variable speed unit.

2. A system for implementing the primary frequency regulation method for a variable speed generator unit based on power setpoint correction as described in claim 1, characterized in that... Specifically, the system includes a parameter acquisition module, an electromagnetic power change calculation module, a mechanical-hydraulic control quantity calculation module, and a primary frequency regulation module. The output of the parameter acquisition module is connected to the inputs of the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module. The outputs of the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module are connected to the input of the primary frequency regulation module. The output of the primary frequency regulation module is connected to the target variable-speed generator set. The parameter acquisition module acquires the real-time operating parameters of the target variable-speed generator set and uploads the data to the electromagnetic power change calculation module and the mechanical-hydraulic control quantity calculation module. The electromagnetic power change calculation module calculates the electromagnetic power change corresponding to the primary frequency regulation action based on the acquired parameter information and outputs it to the primary frequency regulation module. The mechanical-hydraulic control quantity calculation module calculates the control quantity of the mechanical-hydraulic system of the target variable-speed generator set based on the acquired parameter information, inputs it into the mechanical-hydraulic system to obtain the mechanical-hydraulic control quantity, and outputs the mechanical-hydraulic control quantity to the primary frequency regulation module. The primary frequency regulation module completes the primary frequency regulation of the variable-speed generator set based on the received electromagnetic power change and mechanical-hydraulic control quantities.

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