Primary frequency modulation method and system based on fixed rotating speed of variable speed hydroelectric generating unit

Abstract

The application discloses a kind of variable-speed hydroelectric generating set primary frequency modulation methods based on unit rotating speed fixation, including obtaining unit real-time operating parameter and unit parameter;Converter calculates electromagnetic power variation according to target electromagnetic power;Calculate the first opening control quantity and the second opening control quantity of unit;Calculate the mechanical hydraulic system control quantity in unit;Mechanical hydraulic system control quantity is input to mechanical hydraulic control system to obtain mechanical power variation;According to electromagnetic power variation and mechanical power variation, complete target variable-speed hydroelectric generating set primary frequency modulation.The application further discloses a kind of system for implementing the variable-speed hydroelectric generating set primary frequency modulation method based on unit rotating speed fixation of the application.The application adjusts unit operating speed according to target power value, not only realizes the variable-speed hydroelectric generating set primary frequency modulation based on unit rotating speed fixation, but also has high reliability, good stability and better effect.

Description

Technical Field

[0001] This invention belongs to the field of generator control technology, specifically relating to a method and system for primary frequency regulation of a variable speed hydropower unit based on a fixed generator speed. 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 more and more new energy power generation systems being connected to the grid, the uncertainty of their output has placed unprecedented operational pressure on the power system. Pumped storage power stations possess excellent peak-shaving and frequency regulation capabilities, making them one of the important methods for peak-shaving and frequency regulation in the power system. Therefore, the primary frequency regulation control of pumped storage power station units is particularly important.

[0004] Currently, pumped storage power stations generally use traditional hydroelectric generators or constant-speed pumped storage units. However, due to factors such as vibration zones and pressure pulsations, these units are very difficult to operate below 40% of their rated load, and their efficiency also drops significantly when deviating from the design operating point. Therefore, traditional pumped storage power station units are gradually becoming unsuitable for modern power systems.

[0005] Variable-speed hydropower units have advantages such as a wide operating range, a large adjustable range of unit power, and high operating efficiency under steady-state conditions, and are considered the preferred unit for pumped storage power stations in the future. However, if the primary frequency regulation method of traditional pumped storage power stations is used to regulate the primary frequency of variable-speed hydropower units, problems such as slow primary frequency regulation response, severe wear of the relay, and the unit's operating conditions deviating from the high-efficiency range will occur. Summary of the Invention

[0006] One of the objectives of this invention is to provide a highly reliable, stable, and effective method for primary frequency regulation of a variable-speed hydropower unit based on a fixed unit speed.

[0007] The second objective of this invention is to provide a system for implementing the primary frequency regulation method of a variable speed hydropower unit based on a fixed unit speed.

[0008] The method for primary frequency regulation of a variable-speed hydropower unit based on a fixed unit speed provided by this invention includes the following steps:

[0009] Steps for obtaining the real-time operating parameters and unit parameters of the target variable-speed hydropower unit;

[0010] The steps for calculating the electromagnetic power change corresponding to the primary frequency regulation action based on the target electromagnetic power of the converter of the target variable speed hydropower unit;

[0011] The steps for calculating the first opening control quantity of the target variable speed hydropower unit based on the obtained parameter information;

[0012] The steps for calculating the second opening control quantity of the target variable speed hydropower unit based on the obtained parameter information and combined with the comprehensive characteristic curve data of the target variable speed hydropower unit.

[0013] The steps for calculating the control quantities of the mechanical hydraulic system in the variable speed hydro-generator unit based on the obtained first and second opening control quantities;

[0014] The step of inputting the obtained mechanical hydraulic system control quantity into the mechanical hydraulic control system to obtain the corresponding mechanical power change quantity;

[0015] Based on the obtained changes in electromagnetic power and mechanical power, the first step of frequency regulation of the target variable-speed hydroelectric generator unit is completed.

[0016] In the above steps, the unit speed of the target variable speed hydroelectric generator is fixed at the optimal target speed under the current head and current power.

[0017] The step of calculating the first opening control value of the target variable speed hydropower unit based on the acquired parameter information specifically includes the following steps:

[0018] Obtain the measured frequency f and the reference frequency f of the power grid. ref ;

[0019] The obtained frequency values ​​f and f ref Subtraction yields the frequency difference f ref -f, and pass the frequency difference through a manually set dead zone E. f The frequency control quantity Δf is obtained as Δf = (f ref -f)*E f Dead zone link E f The calculation formula is

[0020] By passing the frequency control quantity Δf through a proportional element, the first opening control quantity y1 of the target variable speed hydroelectric generator is obtained as y1 = Δf * K. p1 Among them, K p1 The proportional coefficient of the proportional element is set to... e p The permanent interpolation coefficients for the power of the target variable speed hydroelectric generator are given.

[0021] The step of calculating the second opening control value of the target variable speed hydropower unit based on the acquired parameter information and the comprehensive characteristic curve data of the target variable speed hydropower unit specifically includes the following steps:

[0022] Obtain the target electromagnetic power P ref and the current head H of the target variable speed hydroelectric generator unit;

[0023] Based on the power calculation formula of the target variable speed hydroelectric generator unit The intermediate variable Q was calculated. 11 η, and then based on the comprehensive characteristic curve of the target variable speed hydropower unit. The basic opening control value y* is calculated; where P m Let γ be the power of the turbine in the target variable-speed hydroelectric generator unit, γ be the specific weight of water, D1 be the turbine runner diameter, and Q be the specific power of the turbine. 11 Let η be the unit flow rate of the turbine in the target variable-speed hydropower unit, η be the efficiency of the turbine in the target variable-speed hydropower unit, a be the guide vane opening of the turbine in the target variable-speed hydropower unit, and n be the flow rate of the turbine. 11 The unit speed of the turbine in the target variable speed hydropower unit;

[0024] The obtained basic opening control quantity y* is then processed through a proportional element to obtain the second opening control quantity y2 of the target variable speed hydroelectric generator, which is y2 = y*·K. p2 K p2 The proportional coefficient of the proportional element is set to... y max The target is the maximum guide vane opening of the variable speed hydroelectric generator unit.

[0025] The step of calculating the control quantities of the mechanical hydraulic system in the variable speed hydropower unit based on the obtained first and second opening control quantities specifically includes the following steps:

[0026] Add the first opening control quantity y1 and the second opening control quantity y2 of the target variable speed hydro-generator, and then subtract the per-unit value y of the relay stroke of the target variable speed hydro-generator to obtain the opening control quantity y. c For y c = y1 + y2 - y;

[0027] The opening control value y c After passing through the PID controller, the control quantity of the mechanical hydraulic system in the variable speed hydropower unit is obtained.

[0028] This invention also discloses a system for implementing the aforementioned method for primary frequency regulation of a variable-speed hydro-generator unit based on a fixed unit speed. Specifically, it includes a parameter acquisition module, an electromagnetic power change calculation module, a first opening degree control quantity calculation module, a second opening degree control quantity calculation module, a mechanical-hydraulic system control quantity calculation module, a mechanical power change quantity calculation module, and a primary frequency regulation module. The output of the parameter acquisition module is simultaneously connected to the inputs of the electromagnetic power change quantity calculation module, the first opening degree control quantity calculation module, and the second opening degree control quantity calculation module. The outputs of both the first and second opening degree control quantity calculation modules are connected to the input of the mechanical-hydraulic system control quantity calculation module. The output of the mechanical-hydraulic system control quantity calculation module, the mechanical power change quantity calculation module, and the first input of the primary frequency regulation module are connected in series. The output of the electromagnetic power change quantity calculation module is connected to the second input of the primary frequency regulation module. The output of the primary frequency regulation module is connected to an external variable-speed hydro-generator unit. The parameter acquisition module is used to acquire the real-time operating parameters and unit parameters of the target variable-speed hydro-generator unit and upload the data to the electromagnetic power change quantity calculation module and the first opening degree control quantity calculation module. The system includes a second opening control quantity calculation module; an electromagnetic power change quantity calculation module, which calculates the electromagnetic power change corresponding to the primary frequency regulation action based on the acquired data and the target electromagnetic power, and uploads the data to the primary frequency regulation module; a first opening control quantity calculation module, which calculates the first opening control quantity of the target variable speed hydro-generator based on the acquired data, and uploads the data to the mechanical hydraulic system control quantity calculation module; a second opening control quantity calculation module, which calculates the second opening control quantity of the target variable speed hydro-generator based on the acquired data and the comprehensive characteristic curve data of the target variable speed hydro-generator, and uploads the data to the mechanical hydraulic system control quantity calculation module; a mechanical hydraulic system control quantity calculation module, which calculates the mechanical hydraulic system control quantity in the variable speed hydro-generator based on the acquired data, and uploads the data to the mechanical power change quantity calculation module; a mechanical power change quantity calculation module, which inputs the obtained mechanical hydraulic system control quantity into the mechanical hydraulic control system based on the acquired data to obtain the corresponding mechanical power change quantity, and uploads the data to the primary frequency regulation module; and a primary frequency regulation module, which completes the primary frequency regulation of the target variable speed hydro-generator based on the acquired data.

[0029] The present invention provides a method and system for primary frequency regulation of variable speed hydropower units based on fixed unit speed. By adjusting the unit operating speed according to the target power value, it not only realizes primary frequency regulation of variable speed hydropower units based on fixed unit speed, but also has high reliability, good stability and good effect. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0031] Figure 2 This is a schematic diagram of the constant opening line for turbines with different specific speeds.

[0032] Figure 3 This is a schematic diagram of the system functional modules of the present invention. Detailed Implementation

[0033] like Figure 1 The diagram shown is a flowchart of the method of the present invention: The primary frequency regulation method for a variable speed hydropower unit based on a fixed unit speed provided by the present invention includes the following steps:

[0034] Steps for obtaining the real-time operating parameters and unit parameters of the target variable-speed hydropower unit;

[0035] The steps for calculating the electromagnetic power change corresponding to the primary frequency regulation action based on the target electromagnetic power of the converter of the target variable speed hydropower unit;

[0036] The steps for calculating the first opening control value of the target variable-speed hydropower unit based on the obtained parameter information include the following steps:

[0037] Obtain the measured frequency f and the reference frequency f of the power grid. ref ;

[0038] The obtained frequency values ​​f and f ref Subtraction yields the frequency difference f ref -f, and pass the frequency difference through a manually set dead zone E. f The frequency control quantity Δf is obtained as Δf = (f ref -f)*E f Dead zone link E f The calculation formula is

[0039] By passing the frequency control quantity Δf through a proportional element, the first opening control quantity y1 of the target variable speed hydroelectric generator is obtained as y1 = Δf * K. p1 Among them, K p1 The proportional coefficient of the proportional element is set to... e p The permanent power interpolation coefficient for the target variable-speed hydroelectric generator unit;

[0040] Based on the acquired parameter information and combined with the comprehensive characteristic curve data of the target variable-speed hydropower unit, the steps for calculating the second opening control quantity of the target variable-speed hydropower unit are as follows: In specific implementation, this includes the following steps:

[0041] Obtain the target electromagnetic power P ref and the current head H of the target variable speed hydroelectric generator unit;

[0042] Based on the power calculation formula of the target variable speed hydroelectric generator unit The intermediate variable Q was calculated. 11 η, and then based on the comprehensive characteristic curve of the target variable speed hydropower unit. The basic opening control value y* is calculated; where P m Let γ be the power of the turbine in the target variable-speed hydroelectric generator unit, γ be the specific weight of water, D1 be the turbine runner diameter, and Q be the specific power of the turbine. 11 Let η be the unit flow rate of the turbine in the target variable-speed hydropower unit, η be the efficiency of the turbine in the target variable-speed hydropower unit, a be the guide vane opening of the turbine in the target variable-speed hydropower unit, and n be the flow rate of the turbine. 11 The unit speed of the turbine in the target variable speed hydropower unit;

[0043] The obtained basic opening control quantity y* is then processed through a proportional element to obtain the second opening control quantity y2 of the target variable speed hydroelectric generator, which is y2 = y*·K. p2 K p2 The proportional coefficient of the proportional element is set to... y max The target variable-speed hydroelectric generator unit has the maximum guide vane opening.

[0044] The steps for calculating the control quantities of the mechanical-hydraulic system in a variable-speed hydroelectric generator unit based on the obtained first and second opening control quantities are as follows: In specific implementation, this includes the following steps:

[0045] Add the first opening control quantity y1 and the second opening control quantity y2 of the target variable speed hydro-generator, and then subtract the per-unit value y of the relay stroke of the target variable speed hydro-generator to obtain the opening control quantity y. c For y c = y1 + y2 - y;

[0046] The opening control value y c After passing through the PID controller, the control quantity of the mechanical hydraulic system in the variable speed hydropower unit is obtained;

[0047] The step of inputting the obtained mechanical hydraulic system control quantity into the mechanical hydraulic control system to obtain the corresponding mechanical power change quantity;

[0048] Based on the obtained changes in electromagnetic power and mechanical power, the primary frequency regulation of the target variable-speed hydropower unit is completed. In practice, the changes in electromagnetic power and mechanical power are output to the target variable-speed hydropower unit to complete the primary frequency regulation of the target variable-speed hydropower unit.

[0049] In the above steps, the unit speed of the target variable speed hydropower unit is fixed at the optimal target speed under the current head and current power; the change in opening degree / servoir travel caused by the frequency deviation after one frequency regulation action is superimposed on the optimal target opening degree / servoir travel;

[0050] This invention sacrifices the rapid adjustment characteristics of electromagnetic power, allowing the electromagnetic power to follow changes in the turbine's prime mover output, thus maintaining a constant unit speed (at the optimal target speed value under the current head and power settings). The turbine output is adjusted by changing the prime mover's opening. This invention is applicable to... Figure 2 The impulse turbine, medium-to-high specific speed mixed-flow turbine, and axial-flow fixed-blade turbine shown solves the problem of difficult primary frequency regulation in medium-to-high specific speed turbines. When the system frequency fluctuation is small, the change in opening is small, the offset of the intersection point of the same unit speed and two equal opening lines is small, and the efficiency change between the two operating points before and after the primary frequency regulation is not significant. This method mainly achieves power change by adjusting guide vanes or nozzles, and the mechanical hydraulic system operates relatively frequently.

[0051] The present invention provides a primary frequency regulation method for variable speed hydropower units based on fixed unit speed. Under primary frequency regulation, the electromagnetic power response is fast and the turbine operating efficiency is high under steady-state conditions. It realizes the primary frequency regulation response of various variable speed hydropower units (including medium specific speed turbines, high speed turbines and impulse turbines, etc.) under variable speed operation.

[0052] like Figure 3The 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 hydro-generator unit based on a fixed unit speed specifically includes a parameter acquisition module, an electromagnetic power change calculation module, a first opening control quantity calculation module, a second opening control quantity calculation module, a mechanical hydraulic system control quantity calculation module, a mechanical power change quantity calculation module, and a primary frequency regulation module. The output of the parameter acquisition module is simultaneously connected to the input of the electromagnetic power change quantity calculation module, the input of the first opening control quantity calculation module, and the input of the second opening control quantity calculation module. The outputs of the first and second opening control quantity calculation modules are both connected to the input of the mechanical hydraulic system control quantity calculation module. The output of the mechanical hydraulic system control quantity calculation module, the mechanical power change quantity calculation module, and the first input of the primary frequency regulation module are connected in series. The output of the electromagnetic power change quantity calculation module is connected to the second input of the primary frequency regulation module. The output of the primary frequency regulation module is connected to an external variable-speed hydro-generator unit. The parameter acquisition module is used to acquire the real-time operating parameters and unit parameters of the target variable-speed hydro-generator unit and upload the data to the electromagnetic power change quantity calculation module, the first opening control quantity calculation module, the second opening control quantity calculation module, and the first opening control quantity calculation module. The system comprises the following modules: an opening control quantity calculation module and a second opening control quantity calculation module; an electromagnetic power change quantity calculation module, which calculates the electromagnetic power change corresponding to the primary frequency regulation action based on the acquired data and the target electromagnetic power, and uploads the data to the primary frequency regulation module; a first opening control quantity calculation module, which calculates the first opening control quantity of the target variable speed hydro-generator based on the acquired data, and uploads the data to the mechanical hydraulic system control quantity calculation module; a second opening control quantity calculation module, which calculates the second opening control quantity of the target variable speed hydro-generator based on the acquired data and the comprehensive characteristic curve data of the target variable speed hydro-generator, and uploads the data to the mechanical hydraulic system control quantity calculation module; a mechanical hydraulic system control quantity calculation module, which calculates the mechanical hydraulic system control quantity in the variable speed hydro-generator based on the acquired data, and uploads the data to the mechanical power change quantity calculation module; a mechanical power change quantity calculation module, which inputs the obtained mechanical hydraulic system control quantity into the mechanical hydraulic control system based on the acquired data to obtain the corresponding mechanical power change quantity, and uploads the data to the primary frequency regulation module; and a primary frequency regulation module, which completes the primary frequency regulation of the target variable speed hydro-generator based on the acquired data.

Claims

1. A method for primary frequency regulation of a variable-speed hydropower unit based on a fixed unit speed, comprising the following steps: Steps for obtaining the real-time operating parameters and unit parameters of the target variable-speed hydropower unit; The steps for calculating the electromagnetic power change corresponding to the primary frequency regulation action based on the target electromagnetic power of the converter of the target variable speed hydropower unit; The steps for calculating the first opening control value of the target variable-speed hydropower unit based on the acquired parameter information include the following steps: Obtain the measured frequency of the power grid and the reference frequency of the power grid ; The obtained frequency value and Subtraction yields the frequency difference. The frequency difference is then processed through a manually set dead zone. To obtain the frequency control quantity for Dead zone link The calculation formula is ; frequency control quantity The first opening control value of the target variable speed hydropower unit is obtained through the proportional element. for ;in, The proportional coefficient of the proportional element is set to... , The permanent power interpolation coefficient for the target variable-speed hydroelectric generator unit; Based on the acquired parameter information and combined with the comprehensive characteristic curve data of the target variable-speed hydropower unit, the steps for calculating the second opening control quantity of the target variable-speed hydropower unit are as follows: Obtain target electromagnetic power and the current head of the target variable speed hydroelectric generator unit ; Based on the power calculation formula of the target variable speed hydroelectric generator unit The intermediate variables were calculated. Then, based on the comprehensive characteristic curve of the target variable speed hydropower unit... The basic opening control value is calculated. ;in, The target is the power output of the turbine in a variable-speed hydroelectric generator unit. The density of water, The diameter of the turbine runner. For the unit flow rate of the turbine in the target variable-speed hydropower unit, The goal is to improve the efficiency of the turbine in a variable-speed hydroelectric generator unit. The guide vane opening of the turbine in the target variable speed hydroelectric generator unit. The unit speed of the turbine in the target variable speed hydropower unit; The obtained basic opening control value Then, through proportional processing, the second opening control quantity of the target variable speed hydropower unit is obtained. for , The proportional coefficient of the proportional element is set to... , The target variable-speed hydroelectric generator unit has the maximum guide vane opening. The steps for calculating the control quantities of the mechanical-hydraulic system in a variable-speed hydroelectric generator unit based on the obtained first and second opening control quantities include the following steps: The first opening control value of the target variable speed hydro generator unit and the second opening control quantity of the target variable speed hydroelectric generator unit Add them together, then subtract the per-unit value of the relay stroke of the target variable speed hydroelectric generator. To obtain the opening control quantity for ; Opening control amount After passing through the PID controller, the control quantity of the mechanical hydraulic system in the variable speed hydropower unit is obtained; The step of inputting the obtained mechanical hydraulic system control quantity into the mechanical hydraulic control system to obtain the corresponding mechanical power change quantity; Based on the obtained changes in electromagnetic power and mechanical power, the first step of frequency regulation of the target variable-speed hydroelectric generator unit is completed.

2. The primary frequency regulation method for a variable-speed hydropower unit based on a fixed unit speed according to claim 1, characterized in that... The optimal target speed for the target variable speed hydropower unit is to keep the unit speed fixed at the current head and current power.

3. A system for implementing the primary frequency regulation method of a variable-speed hydropower unit based on a fixed unit speed as described in claim 1 or 2, characterized in that... Specifically, it includes a parameter acquisition module, an electromagnetic power change calculation module, a first opening control quantity calculation module, a second opening control quantity calculation module, a mechanical hydraulic system control quantity calculation module, a mechanical power change quantity calculation module, and a primary frequency modulation module. The output of the parameter acquisition module is simultaneously connected to the input of the electromagnetic power change quantity calculation module, the input of the first opening control quantity calculation module, and the input of the second opening control quantity calculation module. The outputs of the first and second opening control quantity calculation modules are both connected to the input of the mechanical hydraulic system control quantity calculation module. The output of the mechanical hydraulic system control quantity calculation module and the mechanical power change quantity calculation module are connected to the input of the primary frequency modulation module. The first input terminals of the electromagnetic power change calculation module and the primary frequency regulation module are connected in series; the output terminal of the electromagnetic power change calculation module is connected to the second input terminal of the primary frequency regulation module; the output terminal of the primary frequency regulation module is connected to an external variable speed hydro-generator unit; the parameter acquisition module is used to acquire the real-time operating parameters and unit parameters of the target variable speed hydro-generator unit, and upload the data to the electromagnetic power change calculation module, the first opening degree control quantity calculation module, and the second opening degree control quantity calculation module; the electromagnetic power change calculation module is used to calculate the electromagnetic power change corresponding to the primary frequency regulation action based on the acquired data and the target electromagnetic power, and upload the data to the primary frequency regulation module; The first opening control quantity calculation module is used to calculate the first opening control quantity of the target variable speed hydro generator based on the acquired data, and upload the data to the mechanical hydraulic system control quantity calculation module. The second opening control quantity calculation module calculates the second opening control quantity of the target variable speed hydropower unit based on the acquired data and the comprehensive characteristic curve data of the target variable speed hydropower unit, and uploads the data to the mechanical hydraulic system control quantity calculation module. The mechanical hydraulic system control quantity calculation module calculates the mechanical hydraulic system control quantity in the variable speed hydropower unit based on the acquired data, and uploads the data to the mechanical power change quantity calculation module. The mechanical power change quantity calculation module inputs the obtained mechanical hydraulic system control quantity into the mechanical hydraulic control system based on the acquired data to obtain the corresponding mechanical power change quantity, and uploads the data to the primary frequency regulation module. The primary frequency regulation module completes the primary frequency regulation of the target variable speed hydropower unit based on the acquired data.

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