Thermal power generating unit frequency modulation optimization system and method

Abstract

The invention discloses a thermal power generating unit frequency modulation optimization system which comprises a frequency transmitter, a power transmitter, a primary frequency modulation optimization control unit, a unit DEH control system, a unit CCS control system and a unit steam distribution regulating valve. The frequency transmitter and the power transmitter are respectively in communication connection with the primary frequency modulation optimization control unit through a control circuit; the output end of the primary frequency modulation optimization control unit is in communication connection with a set DEH control system and a set CCS control system through a control circuit. The DEH control system is in communication connection with the CCS control system; the DEH control system is in communication connection with the unit steam distribution regulating valve through the electro-hydraulic servo control system; the DEH control system is used for controlling the steam admission amount of the steam turbine generator; and the CCS control system is used for controlling the steam inlet pressure of the steam turbine generator and the actual power of the steam turbine generator. The problem that an existing thermal power generating unit frequency modulation optimization system cannot solve the problem that unit frequency and power signals are inconsistent with power grid examination signals is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid unit frequency regulation, and in particular, relates to a thermal power unit frequency regulation optimization system and method. Background Art

[0002] With the rapid development of new energy and UHV, the frequency fluctuation frequency and amplitude in the actual operation of the power grid have increased significantly. As one of the important means to support the stability of the power grid frequency, the primary frequency regulation performance of the thermal power unit reflects the unit's ability to regulate the grid frequency. Due to the obvious advantages of the frequency regulation quality and regulation ability of thermal power units over those of new energy sources, the current power grid frequency regulation mainly relies on the primary frequency regulation function of thermal power generating units. The existing primary frequency regulation function of thermal power units is to adjust the grid frequency by converting the frequency difference into the increment of the opening of the steam regulating valve of the steam turbine generator. Compared with the rapid fluctuation of the power grid frequency, the action response of the steam regulating valve of the thermal power unit has a certain lag, resulting in a difference between the actual power regulation of the unit and the power grid demand, resulting in the failure of the primary frequency regulation performance indicators of the unit to meet the standards.

[0003] The existing primary frequency regulation optimization technology is mainly aimed at different operating conditions of the unit. According to parameters such as main steam pressure, unit load, and network frequency difference amplitude, the primary frequency regulation comprehensive valve position instruction and load instruction are corrected or compensated, thereby improving the rapidity of the primary frequency regulation action response of the unit, increasing the primary frequency regulation load adjustment amount, and improving the primary frequency regulation performance of the unit.

[0004] The defect of the existing technology is that the existing primary frequency regulation optimization technology improves the frequency regulation performance of the unit by enhancing the local speed inequality or adding additional compensation, but the existing technology fails to solve the problem of inconsistency between the unit frequency and power signals and the power grid assessment signals. Summary of the invention

[0005] Aiming at the problem that the existing frequency regulation optimization system of thermal power units fails to solve the inconsistency between the unit frequency and power signals and the power grid assessment signals, the present invention provides a frequency regulation optimization system and method for thermal power units.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A frequency regulation optimization system for a thermal power unit, comprising a frequency transmitter, a power transmitter, a primary frequency regulation optimization control unit, a unit DEH control system, a unit CCS control system and a unit steam distribution regulating valve;

[0008] The frequency transmitter and the power transmitter are respectively connected to the primary frequency modulation optimization control unit through the control circuit;

[0009] The frequency transmitter is used to monitor the frequency changes of the power grid to which the coal-fired generator is connected;

[0010] The power transmitter is used to monitor the real-time active power of the coal-fired unit and provide power signals for frequency modulation control;

[0011] The output end of the primary frequency regulation optimization control unit is respectively connected to the unit DEH control system and the unit CCS control system through the control circuit;

[0012] DEH control system is connected to CCS control system by communication;

[0013] The DEH control system is connected to the unit steam distribution regulating valve through the electro-hydraulic servo control system;

[0014] The DEH control system is used to control the steam inlet of the steam turbine generator;

[0015] The CCS control system is used to control the steam inlet pressure of the steam turbine generator and the actual power generated by the steam turbine generator;

[0016] The unit's steam regulating valve adjusts the steam flow entering the turbine according to the control system's command signal, thereby controlling the power and speed.

[0017] Furthermore, the primary frequency modulation optimization control unit includes a signal calibration module and a primary frequency modulation optimization module; the frequency transmitter is communicatively connected to the primary frequency modulation optimization module via the signal calibration module; the power transmitter is communicatively connected to the primary frequency modulation optimization module via the signal calibration module;

[0018] The signal calibration module regularly calibrates the unit frequency and power measurement values ​​according to the grid reference signal to ensure signal consistency.

[0019] The primary frequency modulation optimization module uses the changing trend of the frequency mean in the fixed-length sliding window as a feedforward signal to increase the frequency modulation response rate and improve the frequency modulation performance.

[0020] Furthermore, the signal calibration module selects the frequency regulation action related assessment information in the primary frequency regulation assessment result of the thermal power unit as the reference signal, and selects the unit frequency and power measurement values ​​at the starting time and the unit frequency and power measurement values ​​at the frequency difference peak time for comparison and calculation with the reference signal.

[0021] Furthermore, the assessment information related to the frequency modulation action includes the start time of the frequency modulation action, the frequency difference peak time, the initial power, the initial frequency, the peak power and the peak frequency.

[0022] Furthermore, the signal calibration calculation formula in the signal calibration module is:

[0023] f 0i >f i And f 0maxi >f maxi or 0i <f iAnd f 0maxi <f maxi

[0024] f 0i >f i And f 0maxi <f maxi And f i >50 or f 0i <f i And f 0maxi >f maxi And f i <50

[0025] f 0i <f i And f 0maxi >f maxi And f i >50 or f 0i >f i And f 0maxi <f maxi And f i <50

[0026]

[0027] Among them, the unit frequency measurement value at the start time is f, and the unit frequency measurement value at the peak time is f max , the initial frequency of the reference signal is f0, and the peak frequency is f 0max , i is the number of frequency modulation assessments within 24 hours, is the real-time measured value of the unit frequency, and F is the unit frequency value after calibration. The power signal calibration is similar to the frequency signal calibration.

[0028] A method for optimizing frequency regulation of a thermal power unit comprises the following steps:

[0029] S1. Perform fixed-cycle calibration on the unit frequency and power signal to ensure that the unit measurement signal is consistent with the grid assessment signal;

[0030] S2, introducing the network frequency fluctuation trend as a feedforward signal into the primary frequency modulation control unit;

[0031] S3, actuate the steam distribution regulating valve of the steam turbine unit in advance according to the frequency change trend;

[0032] The change of the frequency mean value within a fixed time scale is used as the feedforward signal of a frequency modulation action to act on the valve position control loop of the unit DEH control system and the power control loop of the unit CCS control system respectively;

[0033] The power feed-forward signal calculation formula is:

[0034]

[0035] DF m =F mn -F mn-1

[0036] DP=DF m ×K1

[0037] Among them, F t0 is the frequency measurement value after calibration at time t0, n is the sliding window size, usually 5s, F m is the unit frequency measurement mean within the sliding window scale, DF m is the frequency mean change, DP is the power control feedforward signal, and K1 is the feedforward coefficient. The calculation method of the turbine valve position feedforward signal is similar to that of the power feedforward signal. m The frequency variation trend is characterized. Introducing this signal into frequency control can realize early response of frequency regulation action, reduce the lag time of steam distribution regulating valve of steam turbine unit, and improve the frequency regulation response capability of the unit.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] By regularly calibrating the frequency and power signal measurements, the measured signals are ensured to be consistent with the signals in the power grid assessment system, avoiding the frequency modulation action time being advanced or delayed due to signal errors, and avoiding the frequency modulation action value being too small due to signal errors. In addition, this patent uses the changing trend of the frequency mean in a fixed-length sliding window as the frequency modulation feedforward. When the grid frequency shows a trend of continuous increase or decrease, the unit frequency modulation system will act in advance to avoid the untimely frequency modulation response caused by the lag in the steam distribution valve action, thereby improving the unit frequency modulation assessment pass rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is an overall structural block diagram of a frequency regulation optimization system for a thermal power unit in an embodiment of the present invention;

[0041] Figure 2 This is a block diagram of the internal structure of a primary frequency modulation optimization control unit in an embodiment of the present invention;

[0042] Figure 3 The present invention is an overall flow chart of a method for optimizing frequency regulation of a thermal power unit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments and drawings. The contents mentioned in the implementation modes are not intended to limit the present invention.

[0044] like Figure 1 and 2As shown, this embodiment provides a frequency regulation optimization system for a thermal power unit, including a frequency transmitter, a power transmitter, a primary frequency regulation optimization control unit, a unit DEH control system, a unit CCS control system and a unit steam distribution regulating valve;

[0045] The frequency transmitter and the power transmitter are respectively connected to the primary frequency modulation optimization control unit through the control circuit;

[0046] Frequency transmitters are used to monitor frequency changes in the power grid to which the coal-fired generator is connected; frequency transmitters usually use electronic circuits to measure frequency signals and have high accuracy and stability.

[0047] The power transmitter is used to monitor the real-time active power of the coal-fired unit and provide a power signal for frequency modulation control. The power transmitter calculates the active power of the coal-fired unit by measuring voltage and current and taking into account the influence of power factor.

[0048] The output end of the primary frequency regulation optimization control unit is respectively connected to the unit DEH control system and the unit CCS control system through the control circuit;

[0049] DEH control system is connected to CCS control system by communication;

[0050] The DEH control system is connected to the unit steam distribution regulating valve through the electro-hydraulic servo control system;

[0051] The DEH control system is used to control the steam inlet of the steam turbine generator;

[0052] The CCS control system is used to control the steam inlet pressure of the steam turbine generator and the actual power generated by the steam turbine generator;

[0053] The steam distribution regulating valve of the unit adjusts the steam flow entering the steam turbine according to the command signal of the control system, and controls the power and speed. The steam distribution regulating valve is an important part of the steam turbine regulation system. It controls the steam flow entering the steam turbine by changing the steam flow area, thereby adjusting the power and speed of the steam turbine.

[0054] The primary frequency modulation optimization control unit includes a signal calibration module and a primary frequency modulation optimization module; the frequency transmitter is connected to the primary frequency modulation optimization module through the signal calibration module; the power transmitter is connected to the primary frequency modulation optimization module through the signal calibration module;

[0055] The signal calibration module regularly calibrates the unit frequency and power measurement values ​​according to the grid reference signal to ensure signal consistency.

[0056] The primary frequency modulation optimization module uses the changing trend of the frequency mean in the fixed-length sliding window as a feedforward signal to increase the frequency modulation response rate and improve the frequency modulation performance.

[0057] The signal calibration module selects the frequency regulation action related assessment information in the primary frequency regulation assessment result of the thermal power unit as the reference signal, and selects the unit frequency and power measurement values ​​at the starting time and the unit frequency and power measurement values ​​at the frequency difference peak time for comparison and calculation with the reference signal.

[0058] The assessment information related to the frequency modulation action includes the start time of the frequency modulation action, the frequency difference peak time, the initial power, the initial frequency, the peak power and the peak frequency.

[0059] The signal calibration calculation formula in the signal calibration module is:

[0060] f 0i >f i And f 0maxi >f maxi or 0i <f i And f 0maxi <f maxi

[0061] f 0i >f i And f 0maxi <f maxi And f i >50 or f 0i <f i And f 0maxi >f maxi And f i <50

[0062] f 0i <f i And f 0maxi >f maxi And f i >50 or f 0i >f i And f 0maxi <f maxi And f i <50

[0063]

[0064] Among them, the unit frequency measurement value at the start time is f, and the unit frequency measurement value at the peak time is f max , the initial frequency of the reference signal is f0, and the peak frequency is f 0max , i is the number of frequency modulation assessments within 24 hours, is the real-time measured value of the unit frequency, and F is the unit frequency value after calibration. The power signal calibration is similar to the frequency signal calibration.

[0065] like Figure 3As shown, a method for optimizing frequency regulation of a thermal power unit comprises the following steps:

[0066] S1. Perform fixed-cycle calibration on the unit frequency and power signal to ensure that the unit measurement signal is consistent with the grid assessment signal;

[0067] S2, introducing the network frequency fluctuation trend as a feedforward signal into the primary frequency modulation control unit;

[0068] S3, actuate the steam distribution regulating valve of the steam turbine unit in advance according to the frequency change trend;

[0069] The change of the frequency mean value within a fixed time scale is used as the feedforward signal of a frequency modulation action to act on the valve position control loop of the unit DEH control system and the power control loop of the unit CCS control system respectively;

[0070] The power feed-forward signal calculation formula is:

[0071]

[0072] DF m =F mn -F mn-1

[0073] DP=DF m ×K1

[0074] Among them, F t0 is the frequency measurement value after calibration at time t0, n is the sliding window size, usually 5s, F m is the unit frequency measurement mean within the sliding window scale, DF m is the frequency mean change, DP is the power control feedforward signal, and K1 is the feedforward coefficient. The calculation method of the turbine valve position feedforward signal is similar to that of the power feedforward signal. m The frequency variation trend is characterized. Introducing this signal into frequency control can realize early response of frequency regulation action, reduce the lag time of steam distribution regulating valve of steam turbine unit, and improve the frequency regulation response capability of the unit.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] By regularly calibrating the frequency and power signal measurements, the measured signals are ensured to be consistent with the signals in the power grid assessment system, avoiding the frequency modulation action time being advanced or delayed due to signal errors, and avoiding the frequency modulation action value being too small due to signal errors. In addition, this patent uses the changing trend of the frequency mean in a fixed-length sliding window as the frequency modulation feedforward. When the grid frequency shows a trend of continuous increase or decrease, the unit frequency modulation system will act in advance to avoid the untimely frequency modulation response caused by the lag in the steam distribution valve action, thereby improving the unit frequency modulation assessment pass rate.

[0077] The above is a detailed introduction to a thermal power unit frequency regulation optimization system and method provided by the present application. The description of the specific embodiment is only used to help understand the method and its core idea of ​​the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A frequency regulation optimization system for thermal power units, characterized in that: Including frequency transmitter, power transmitter, primary frequency regulation optimization control unit, unit DEH control system, unit CCS control system and unit steam distribution regulating valve; The frequency transmitter and the power transmitter are respectively connected to the primary frequency modulation optimization control unit through the control circuit; The frequency transmitter is used to monitor the frequency changes of the power grid to which the coal-fired generator is connected; The power transmitter is used to monitor the real-time active power of the coal-fired unit and provide power signals for frequency modulation control; The output end of the primary frequency regulation optimization control unit is respectively connected to the unit DEH control system and the unit CCS control system through the control circuit; DEH control system is connected to CCS control system by communication; The DEH control system is connected to the unit steam distribution regulating valve through the electro-hydraulic servo control system; The DEH control system is used to control the steam inlet of the steam turbine generator; The CCS control system is used to control the steam inlet pressure of the steam turbine generator and the actual power generated by the steam turbine generator; The unit's steam regulating valve adjusts the steam flow entering the turbine according to the control system's command signal, thereby controlling the power and speed.

2. A thermal power unit frequency modulation optimization system according to claim 1, characterized in that: The primary frequency modulation optimization control unit includes a signal calibration module and a primary frequency modulation optimization module; the frequency transmitter is connected to the primary frequency modulation optimization module through the signal calibration module; the power transmitter is connected to the primary frequency modulation optimization module through the signal calibration module; The signal calibration module regularly calibrates the unit frequency and power measurement values ​​according to the grid reference signal; The primary frequency modulation optimization module uses the changing trend of the frequency mean in a fixed-length sliding window as a feedforward signal.

3. A thermal power unit frequency modulation optimization system according to claim 2, characterized in that: The signal calibration module selects the frequency regulation action related assessment information in the primary frequency regulation assessment result of the thermal power unit as the reference signal, and selects the unit frequency and power measurement values ​​at the starting time and the unit frequency and power measurement values ​​at the frequency difference peak time for comparison and calculation with the reference signal.

4. A thermal power unit frequency modulation optimization system according to claim 3, characterized in that: The assessment information related to the frequency modulation action includes the start time of the frequency modulation action, the frequency difference peak time, the initial power, the initial frequency, the peak power and the peak frequency.

5. A thermal power unit frequency regulation optimization system according to claim 4, characterized in that: The signal calibration calculation formula in the signal calibration module is: f 0i >f i And f 0maxi >f maxi or 0i <f i And f 0maxi <f maxi f 0i >f i And f 0maxi <f maxi And f i >50 or f 0i <f i And f 0maxi >f maxi And f i <50 f 0i <f i And f 0maxi >f maxi And f i >50 or f 0i >f i And f 0maxi <f maxi And f i <50 Among them, the unit frequency measurement value at the start time is f, and the unit frequency measurement value at the peak time is f max , the initial frequency of the reference signal is f0, and the peak frequency is f 0max , i is the number of frequency modulation assessments within 24 hours, is the real-time measured value of the unit frequency, and F is the unit frequency value after calibration.

6. A method for optimizing frequency regulation of a thermal power unit, characterized in that: Includes steps: S1. Perform fixed period calibration on the unit frequency and power signal; S2, introducing the network frequency fluctuation trend as a feedforward signal into the primary frequency modulation control unit; S3, actuate the steam distribution regulating valve of the steam turbine unit in advance according to the frequency change trend; The change of the frequency mean value within a fixed time scale is used as the feedforward signal of a frequency modulation action to act on the valve position control loop of the unit DEH control system and the power control loop of the unit CCS control system respectively; The power feed-forward signal calculation formula is: DF m =F mn -F mn-1 DP=DF m ×K1 Among them, F t0 is the frequency measurement value after calibration at time t0, n is the sliding window size, usually 5s, F m is the unit frequency measurement mean within the sliding window scale, DF m is the frequency mean change, DP is the power control feedforward signal, and K1 is the feedforward coefficient.

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