Device and method for improving percent of pass of primary frequency modulation

Abstract

The invention provides a device and method for improving the qualified rate of primary frequency modulation, and the device comprises a rotating speed signal obtaining unit which comprises three rapid-response high-precision frequency measurement devices which are arranged in a redundant manner and are used for measuring the rotating speed of a generator rotor; the first line frequency acquisition unit measures the line frequency of the high-voltage side of the power plant main transformer; the CCS unit generates a CCS instruction according to the AGC instruction and the measured line frequency; the DEH unit performs control valve control according to the measured rotating speed signal and the CCS instruction, and adjusts the machine end power; the power plant PMU unit obtains the actual frequency of the power plant according to the machine end power; scheduling the PMU unit to obtain the preset frequency of the power grid and the actual frequency of the power plant; the assessment unit compares the actual frequency with the preset frequency, does not perform assessment when the actual frequency is matched with the preset frequency, and performs assessment when the actual frequency is not matched with the preset frequency. By using the high-precision frequency measuring device with redundancy design, the frequency resolution can be effectively improved, signal sampling can be accurately controlled, and the qualification rate of examination can be further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid frequency regulation, and in particular relates to a device and method for improving the pass rate of primary frequency regulation. Background Art

[0002] In the power system, the load balance condition is a closed-loop operation, which mainly involves the frequency and power signal quantities. Thermal power units often have large-scale assessment events due to insufficient primary frequency regulation response to the grid load. Analysis shows that it is mainly caused by the fluctuation of frequency, power and other signals, low accuracy, slow response time, asynchronous load response, and the frequency signal used in the grid assessment and the different sources of the thermal power unit measurement signal.

[0003] There is a dead zone in the primary frequency modulation logic. The dead zone of the frequency modulation of thermal power units is generally 2r / min. If the speed signal is used, the frequency modulation amplitude is often insufficient and hysteresis problems often occur in the actual response of the primary frequency modulation of the unit. At the same time, many thermal power units currently use magnetic resistance probes for speed measurement and the number of teeth is generally designed to be 60. This causes a large deviation in the actual speed feedback and a long delay time, and there is a low speed card accuracy, that is, there is no way to achieve a resolution of 0.1 revolutions.

[0004] Therefore, in view of the above problems, it is necessary to propose a device and method that can improve the primary frequency modulation pass rate. Summary of the invention

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art and to provide a device and method for improving the primary frequency modulation qualification rate.

[0006] In one aspect of the present disclosure, a device for improving a primary frequency modulation pass rate is provided, the device comprising:

[0007] The speed signal acquisition unit includes three redundantly set fast-response high-precision frequency measurement devices for measuring the speed of the generator rotor;

[0008] A first line frequency acquisition unit, comprising three redundantly set fast-response high-precision frequency measurement devices, for measuring the line frequency on the high-voltage side of the main transformer of the power plant;

[0009] A CCS unit for generating a CCS command based on the AGC command and the measured line frequency;

[0010] The DEH unit is used to perform throttle control based on the measured speed signal and CCS command, and further adjust the machine-end power;

[0011] The power plant PMU unit is used to obtain the actual frequency of the power plant based on the power at the machine end;

[0012] The dispatching PMU unit is used to obtain the preset frequency of the power grid and the actual frequency of the power plant;

[0013] The assessment unit is used to compare the actual frequency of the power plant with the preset frequency of the power grid. When the two match, no assessment is performed, and when the two do not match, assessment is performed.

[0014] Optionally, in the rotation speed signal acquisition unit, two of the fast-response high-precision frequency measurement devices collect signals synchronously, and the other fast-response high-precision frequency measurement device is kept as a standby.

[0015] Optionally, in the first line frequency acquisition unit, one of the fast-response high-precision frequency measurement devices is connected to the PT and CT on the high-voltage side of the main transformer to measure frequency, voltage, and current signals;

[0016] Another fast-response, high-precision frequency measurement device is connected to the excitation transformer, high-voltage plant transformer, and starting standby transformer to collect and calculate current, voltage, and power signals;

[0017] Another fast response high precision frequency measurement device is available as a backup.

[0018] Optionally, the fast response high precision frequency measurement device adopts step-by-step slip sampling calculation.

[0019] Optionally, the device further comprises a valve adjustment control unit connected to the DEH unit, for adjusting the valve according to instructions of the DEH unit.

[0020] Optionally, the valve adjustment control unit is also connected to the speed signal acquisition unit.

[0021] Optionally, the device further comprises a machine-end power control unit connected to the threshold control unit, for controlling the machine-end power according to the threshold instruction.

[0022] Optionally, the machine-end power control unit is also electrically connected to the DEH unit and the CCS unit.

[0023] Optionally, the DEH unit is also electrically connected to the first line frequency acquisition unit;

[0024] The speed signal acquisition unit is also electrically connected to the CCS unit.

[0025] Another aspect of the present disclosure provides a method for improving a primary frequency modulation pass rate, the method comprising:

[0026] The generator rotor speed is measured using three redundant fast-response, high-precision frequency measurement devices;

[0027] The line frequency on the high voltage side of the power plant main transformer is measured using three redundant fast response and high precision frequency measurement devices;

[0028] Generate CCS commands based on AGC commands and measured line frequency;

[0029] The throttle control is performed according to the measured speed signal and CCS command to further adjust the power at the machine end;

[0030] Get the actual frequency of the power plant according to the power at the machine end;

[0031] Obtain the preset frequency of the power grid and the actual frequency of the power plant;

[0032] Based on the comparison between the actual frequency of the power plant and the preset frequency of the power grid, if the two match, no assessment is performed; otherwise, an assessment is performed.

[0033] Optionally, three redundantly configured fast-response high-precision frequency measurement devices are used to measure the generator rotor speed, including:

[0034] Two of the fast-response high-precision frequency measuring devices collect synchronously the generator rotor speed, and the other fast-response high-precision frequency measuring device is used as a standby.

[0035] Optionally, three redundantly set fast response high-precision frequency measuring devices are used to measure the line frequency on the high voltage side of the main transformer of the power plant, including:

[0036] One of the fast-response high-precision frequency measuring devices is connected to the PT and CT on the high-voltage side of the main transformer to measure frequency, voltage and current signals; the other fast-response high-precision frequency measuring device is connected to the excitation transformer, high-voltage plant transformer and starting standby transformer to collect and calculate current, voltage and power signals; the other fast-response high-precision frequency measuring device is kept as a standby.

[0037] The present disclosure proposes a device and method for improving the pass rate of primary frequency regulation, the device comprising: a speed signal acquisition unit, including three redundantly set fast response high-precision frequency measurement devices, for measuring the speed of the generator rotor; a first line frequency acquisition unit, including three redundantly set fast response high-precision frequency measurement devices, for measuring the line frequency on the high-voltage side of the main transformer of the power plant; a CCS unit, for generating a CCS instruction according to an AGC instruction and a measured line frequency; a DEH unit, for performing a gate control according to the measured speed signal and the CCS instruction, and further adjusting the machine-end power; a power plant PMU unit, for obtaining the actual frequency of the power plant according to the machine-end power; a dispatching PMU unit, for obtaining the preset frequency of the power grid and the actual frequency of the power plant; an assessment unit, for comparing the actual frequency of the power plant with the preset frequency of the power grid, and not conducting an assessment when the two match, and conducting an assessment when the two do not match. By improving the speed signal acquisition unit and the line frequency acquisition unit, and using a redundantly designed high-precision frequency measurement device, the frequency resolution can be effectively improved, the signal sampling can be accurately controlled, and the pass rate of the assessment can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of a device for improving the primary frequency modulation pass rate according to an embodiment of the present disclosure;

[0039] Figure 2 A schematic diagram of improving the primary frequency modulation pass rate according to another embodiment of the present disclosure;

[0040] Figure 3 The present invention is a flowchart of a method for improving the primary frequency modulation qualification rate according to another embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0042] like Figure 1 and Figure 2As shown, in one aspect of the present disclosure, a device 100 for improving the pass rate of primary frequency regulation is proposed, and the device includes: a speed signal acquisition unit 110, including three redundantly set fast-response high-precision frequency measurement devices, for measuring the speed of the generator rotor; a first line frequency acquisition unit 120, including three redundantly set fast-response high-precision frequency measurement devices, for measuring the line frequency on the high-voltage side of the main transformer of the power plant; a CCS unit 130, for generating a CCS instruction according to the AGC instruction and the measured line frequency; a DEH unit 140, for performing a throttle control according to the measured speed signal and the CCS instruction, and further adjusting the machine-end power; a power plant PMU unit 150, for obtaining the actual frequency of the power plant according to the machine-end power; a dispatching PMU unit 160, for obtaining the preset frequency of the power grid and the actual frequency of the power plant; an assessment unit 170, for comparing the actual frequency of the power plant with the preset frequency of the power grid, and not performing an assessment when the two match, and performing an assessment when the two do not match.

[0043] In this embodiment, the speed signal acquisition unit and the first line frequency acquisition unit adopt a fast response high-precision frequency measurement device. The device adopts an integrated digital circuit design, and the EMC anti-interference capability reaches above the severe level 3. The FFT full-cycle Fourier algorithm and the dual-spectrum interpolation algorithm are used to achieve reliable frequency measurement, and the frequency resolution reaches 0.001Hz. That is, by improving the speed signal acquisition unit and the line frequency acquisition unit and using a high-precision frequency measurement device with redundant design, the frequency resolution can be effectively improved, and the signal sampling can be accurately controlled, thereby improving the pass rate of the assessment.

[0044] It should be noted that the fast-response, high-precision generator power measurement device of this embodiment adopts an integrated digital circuit design, and its EMC anti-interference capability reaches above the severe level 3. The device adopts a gradual sliding point sampling calculation to ensure that the power and other measurement signals are not distorted under transient conditions. The output curve is basically consistent with the actual power signal, and is accurately fed back to the unit's control system in real time.

[0045] It should be further explained that in the speed signal acquisition unit, two of the fast-response high-precision frequency measurement devices are used to collect signals, and the other fast-response high-precision frequency measurement device is used as a backup, which effectively improves the reliability of the DEH and DCS systems, meets the requirements of the DEH and AGC systems, reduces system misadjustments, and ensures stable operation of the unit.

[0046] It is still necessary to explain that, in this embodiment, the secondary side transmitter of the transmitter group is technically transformed into three fast-response high-precision frequency measuring devices (dual-loop measurement, three redundant frequency signals). For example, in the first line frequency acquisition unit, one of the fast-response high-precision frequency measuring devices is connected to the PT and CT on the high-voltage side of the main transformer for measuring frequency, voltage, and current signals; another fast-response high-precision frequency measuring device is connected to the excitation transformer, the high-voltage plant transformer, and the starting standby transformer for collecting and calculating current, voltage, and power signals; another fast-response high-precision frequency measuring device is used as a backup, thereby effectively improving the reliability of the primary frequency modulation system.

[0047] Furthermore, if Figure 1 As shown, the device 100 also includes a threshold control unit 180 connected to the DEH unit 140 , which is used to perform threshold adjustment according to instructions issued by the DEH unit 140 .

[0048] It should be noted that the DEH unit is a digital electro-hydraulic control system. The DEH system receives load instructions from the power grid dispatching center or the unit coordinated control system (CCS), and then accurately controls the output power of the steam turbine by adjusting the opening of the steam inlet valve to meet the load requirements of the power grid for the unit. Secondly, during the start-up of the steam turbine, the DEH unit accurately controls the speed of the steam turbine by controlling the opening of the steam inlet valve of the steam turbine. For example, when the steam turbine starts from a stationary state, the DEH unit will gradually open the steam inlet valve according to the preset start-up curve, so that the turbine speed rises steadily until it reaches the rated speed. In addition, the DEH unit is also connected to the first line frequency acquisition unit. When the unit is operating normally, if the power grid frequency changes, the DEH system can also quickly adjust the turbine speed to maintain the stability of the power grid frequency. This is achieved by real-time adjustment of the steam inlet amount of the steam turbine. Changes in the steam inlet amount will cause changes in the output power of the steam turbine, thereby keeping the speed within the specified range.

[0049] Furthermore, if Figure 1 As shown, the valve control unit 180 is also connected to the speed signal acquisition unit 110. The valve control unit 180 accurately adjusts the valve opening according to the received speed signal and a preset start-up curve or control strategy, thereby controlling the steam flow entering the steam turbine.

[0050] Furthermore, if Figure 1 As shown, the device 100 further includes a machine-side power control unit 190 connected to the threshold control unit 180 for controlling the machine-side power according to the threshold command. In addition, the machine-side power control unit 190 is also electrically connected to the DEH unit 140 and the CCS unit 130.

[0051] Among them, the valve control unit issues valve control instructions, and the machine-end power control unit controls the machine-end power according to these instructions. When the valve control instructions change, the machine-end power control unit will adjust the output power of the generator accordingly. For example, when the load demand of the power grid increases, the valve control unit will issue an instruction to open the regulating valve, and the machine-end power control unit will increase the machine-end power output according to this instruction to meet the power demand of the power grid. This connection method ensures that the machine-end power can quickly and accurately follow the changes in the valve control instructions, maintaining the stability and reliability of the unit power output.

[0052] Furthermore, the DEH (digital electro-hydraulic control system) unit is mainly responsible for the speed control of the steam turbine, but after the unit is connected to the grid, its function is also related to power control. The power control unit at the machine end is connected to the DEH unit to achieve coordinated control of speed and power.

[0053] In addition, the CCS (coordinated control system) unit is responsible for comprehensive coordinated control of multiple subsystems of the unit to meet the grid load requirements and ensure the stable operation of the unit. The power control unit at the machine end is connected to the CCS unit and can receive comprehensive control instructions from the CCS unit.

[0054] It should be noted that the CCS unit proposed in this embodiment is a coordinated control system, which can accurately control the power output of the generator set according to the load demand of the power grid. For example, when the load of the power grid increases, CCS will adjust the parameters such as the fuel supply amount and the air intake amount to increase the power output of the generator set to meet the power grid's demand for electricity; conversely, when the load of the power grid decreases, CCS will reduce the power output of the generator set accordingly. Of course, multi-variable coordinated control can also be achieved, and by coordinating multiple variables, it is ensured that the generator set can operate stably and efficiently under different working conditions. For example, when adjusting the power output, CCS will simultaneously consider the change of the main steam pressure to avoid excessive fluctuations in the main steam pressure due to power regulation, thereby affecting the safety and stability of the unit. Of course, in addition to this, it can also be integrated with other systems, for example, with the DEH unit, AGC instructions, etc. It receives instructions from the AGC to adjust the power generation of the unit; at the same time, it works in conjunction with the DEH unit, the DEH unit is mainly responsible for the control of the steam turbine, and the CCS unit coordinates the control of the unit from a more macro perspective, and the two together ensure the stable operation of the unit.

[0055] Furthermore, if Figure 1As shown, the DEH unit 140 is also electrically connected to the first line frequency acquisition unit 120. When the grid frequency changes, the first line frequency acquisition unit 120 transmits the frequency change signal to the DEH unit 140. This connection helps to optimize the operation of the unit under different frequency conditions. By acquiring line frequency information in real time, the DEH unit can reasonably adjust the operating parameters of the steam turbine when the grid frequency fluctuates, so that the unit can quickly respond to changes in grid frequency and maintain a more economical operating state.

[0056] In addition, if Figure 1 As shown, the speed signal acquisition unit 110 is also electrically connected to the CCS unit 130. The speed signal acquisition unit 110 monitors the speed of the unit in real time, and the CCS unit 130 is responsible for comprehensively coordinating the operating parameters such as the power output of the unit. When the speed of the unit changes, the speed signal acquisition unit 110 transmits the speed signal to the CCS unit 130. This connection helps to optimize the overall performance of the unit. The CCS unit can better coordinate the operation of each subsystem in the unit according to the speed signal by connecting to the speed signal acquisition unit.

[0057] It should also be understood that the dispatching PMU unit 160 is used to obtain the actual frequency of the power plant PMU unit on the one hand, and is also connected to the second line frequency acquisition unit 161 on the other hand to obtain the preset frequency of a certain measuring point in the regional power grid, such as Figure 1 The two frequencies are further transmitted to the assessment unit to evaluate whether an assessment is required.

[0058] Furthermore, if Figure 1 As shown, the scheduling PMU unit 160 of this embodiment is also connected to the second line frequency acquisition unit 161, which is used to obtain the line frequency preset at a certain measuring point of the regional power grid.

[0059] This implementation method realizes the homologous acquisition of the primary frequency modulation signal by integrating and processing the speed signal of the generator rotor, the high-voltage side of the main transformer of the power plant, and the line frequency signal of a certain measuring point of the regional power grid. By transforming the signal to the same source, the difference and interference between different signal sources are reduced, making the signals received by each control system more consistent, thereby enhancing the reliability of the entire frequency modulation system under complex working conditions. In addition, by transforming the secondary side transmitter of the transmission group into three fast-response high-precision frequency measurement devices, dual-loop measurement and three redundancies of frequency signals are realized. This redundant design can ensure that the system can still obtain accurate frequency signals normally when a certain measuring device fails, avoiding the failure of the primary frequency modulation function due to a single point failure.

[0060] like Figure 2 and Figure 3As shown, another aspect of the present disclosure provides a method S200 for improving the primary frequency modulation pass rate, which specifically includes the following steps S210 to S270:

[0061] S210. Measure the generator rotor speed using three redundantly configured fast-response high-precision frequency measurement devices.

[0062] Specifically, two of the three redundant fast-response high-precision frequency measurement devices are used to collect signals, and the other fast-response high-precision frequency measurement device is used as a standby. The fast-response high-precision frequency measurement device is used to measure the rotational speed of the generator rotor, which can effectively improve the frequency resolution to 0.001 Hz.

[0063] S220, using three redundant fast-response high-precision frequency measuring devices to measure the line frequency on the high-voltage side of the power plant main transformer.

[0064] Specifically, the secondary side transmitter at the generator end is technically transformed into three fast-response high-precision generator power measuring devices (three redundant power signals). In the first line frequency acquisition unit, one fast-response high-precision frequency measuring device is connected to the PT and CT on the high-voltage side of the main transformer for measuring frequency, voltage and current signals; another fast-response high-precision frequency measuring device is connected to the excitation transformer, the high-voltage plant transformer and the starting standby transformer for collecting and calculating current, voltage and power signals; another fast-response high-precision frequency measuring device is used as a standby. By measuring the line frequency on the high-voltage side of the main transformer of the power plant through the three redundant devices, the reliability of the DEH and DCS systems can be improved, the requirements of the DEH and AGC systems can be met, the system misadjustment can be reduced, and the stable operation of the unit can be ensured.

[0065] S230: Generate a CCS command according to the AGC command and the measured line frequency.

[0066] Specifically, the AGC system of the power grid dispatching center generates AGC instructions based on the real-time operating status of the power grid, and uses the CCS system to combine the AGC instructions with the unit's own operating parameters. After complex control algorithm calculations, specific CCS instructions are generated. The instructions include power control. For example, according to the AGC instructions and signals such as the power grid frequency, the CCS accurately controls the power output of the unit. When the power grid frequency fluctuates, the CCS automatically adjusts the power output of the unit within a certain range based on the frequency signal to help maintain the stability of the power grid frequency.

[0067] S240, performing throttle control according to the measured speed signal and the CCS command, and further adjusting the machine-end power.

[0068] Specifically, after receiving the speed signal and CCS instruction, the DEH unit will conduct a comprehensive analysis and judgment based on the pre-set control algorithm. If the speed signal indicates that the unit speed is normal, but the CCS instruction requires an increase in the machine-end power, the DEH unit will increase the throttle opening at a certain rate to gradually increase the steam flow, thereby achieving an increase in the machine-end power. If the speed signal shows that the speed deviates from the rated value, the DEH unit will first adjust the throttle opening according to the speed deviation to restore the speed to the normal range as soon as possible, while taking into account the power regulation requirements of the CCS instruction.

[0069] S250, obtaining the actual frequency of the power plant according to the machine-end power.

[0070] Specifically, the PMU unit of a power plant is a phasor measurement unit. At the generator end, a sensor dedicated to measuring power is installed. These sensors are usually based on the principle of electromagnetic induction or other related technologies, and can sense the current and voltage signals at the generator end in real time, thereby obtaining the actual frequency of the power plant.

[0071] S260: Obtain a preset frequency of the power grid and an actual frequency of the power plant.

[0072] Specifically, the line frequency of a certain measuring point in the regional power grid is acquired through the second line frequency acquisition unit, thereby obtaining the preset frequency of the measuring point, and at the same time, the actual frequency of the power plant obtained by the PMU unit of the power plant can also be acquired.

[0073] S270. Compare the actual frequency of the power plant with the preset frequency of the power grid. If the two match, no assessment is performed. If the two do not match, an assessment is performed.

[0074] Specifically, an evaluation is performed based on the preset frequency obtained by the dispatching PMU and the actual frequency of the power plant. When the two match, it means that the unit is operating normally. When the two do not match, it means that an assessment is needed.

[0075] The present disclosure proposes a device and method for improving the primary frequency modulation pass rate, which has the following beneficial effects compared with the prior art:

[0076] First, the present disclosure adopts a fast-response high-precision generator power measurement device, which adopts an integrated digital circuit design, and the EMC anti-interference ability reaches the severe level 3 or above. The algorithm calculation frequency based on the fast-response high-precision frequency measurement device is used to accurately control the signal sampling, and the gradual sliding point sampling calculation is performed to ensure that the power and other measurement signals are not distorted under transient conditions, and the output curve is basically consistent with the actual power signal, and the feedback is given to the unit control system in real time and accurately;

[0077] Second, the secondary-side transmitter at the generator end is technically transformed into three fast-response, high-precision generator power measurement devices (three redundant power signals) to improve the reliability of the DEH and DCS systems, meet the requirements of the DEH and AGC systems, reduce system misadjustments, and ensure stable operation of the unit.

[0078] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A device for improving the primary frequency modulation pass rate, characterized in that: The device comprises: The speed signal acquisition unit includes three redundantly set fast-response high-precision frequency measurement devices for measuring the speed of the generator rotor; A first line frequency acquisition unit, comprising three redundantly set fast-response high-precision frequency measurement devices, for measuring the line frequency on the high-voltage side of the main transformer of the power plant; A CCS unit for generating a CCS command based on the AGC command and the measured line frequency; DEH unit is used to perform throttle control according to the measured speed signal and CCS command, and further adjust the power at the machine end; The power plant PMU unit is used to obtain the actual frequency of the power plant based on the power at the machine end; The dispatching PMU unit is used to obtain the preset frequency of the power grid and the actual frequency of the power plant; The assessment unit is used to compare the actual frequency of the power plant with the preset frequency of the power grid. When the two match, no assessment is performed, and when the two do not match, assessment is performed.

2. The device according to claim 1, characterized in that In the rotation speed signal acquisition unit, two of the fast-response high-precision frequency measurement devices collect signals synchronously, and the other fast-response high-precision frequency measurement device is kept as a standby.

3. The device according to claim 1, characterized in that In the first line frequency acquisition unit, one of the fast-response high-precision frequency measurement devices is connected to the PT and CT on the high-voltage side of the main transformer to measure frequency, voltage, and current signals; Another fast-response, high-precision frequency measurement device is connected to the excitation transformer, high-voltage plant transformer, and starting standby transformer to collect and calculate current, voltage, and power signals; Another fast response high precision frequency measurement device is available as a backup.

4. The device according to claim 1, characterized in that The fast response high precision frequency measurement device adopts step-by-step slip sampling calculation.

5. The device according to claim 1, characterized in that The device also includes a valve adjustment control unit connected to the DEH unit, which is used to adjust the valve according to the instruction of the DEH unit. The valve adjustment control unit is also connected to the speed signal acquisition unit.

6. The device according to claim 5, characterized in that The device also includes a machine-end power control unit connected to the threshold control unit, which is used to control the machine-end power according to the threshold instruction.

7. The device according to claim 6, characterized in that The machine-end power control unit is also electrically connected to the DEH unit and the CCS unit; and / or, The DEH unit is also electrically connected to the first line frequency acquisition unit; and / or, The speed signal acquisition unit is also electrically connected to the CCS unit.

8. A method for improving the primary frequency modulation qualification rate, characterized in that: The method comprises: The generator rotor speed is measured using three redundant fast-response, high-precision frequency measurement devices; The line frequency on the high voltage side of the power plant main transformer is measured using three redundant fast response and high precision frequency measurement devices; Generate CCS commands based on AGC commands and measured line frequency; The throttle control is performed according to the measured speed signal and CCS command to further adjust the machine-end power; Get the actual frequency of the power plant according to the power at the machine end; Obtain the preset frequency of the power grid and the actual frequency of the power plant; Based on the comparison between the actual frequency of the power plant and the preset frequency of the power grid, if the two match, no assessment is performed; otherwise, an assessment is performed.

9. The method according to claim 8, characterized in that The method of measuring the generator rotor speed by using three redundantly arranged fast-response high-precision frequency measurement devices includes: Two of the fast-response high-precision frequency measuring devices collect synchronously the generator rotor speed, and the other fast-response high-precision frequency measuring device is used as a standby.

10. The method according to claim 8, characterized in that The method of measuring the line frequency on the high voltage side of the main transformer of a power plant by using three redundantly set fast response high precision frequency measuring devices comprises: One of the fast-response high-precision frequency measuring devices is connected to the PT and CT on the high-voltage side of the main transformer to measure frequency, voltage and current signals; the other fast-response high-precision frequency measuring device is connected to the excitation transformer, high-voltage plant transformer and starting standby transformer to collect and calculate current, voltage and power signals; the other fast-response high-precision frequency measuring device is kept as a standby.

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