Impact type hydroelectric generating set isolated network regulation performance test method

Abstract

The invention relates to an impact type hydroelectric generating set isolated network regulation performance test method, and belongs to the technical field of hydroelectric generating set isolated network control. The test method comprises the following steps of: 1, static test: simulating unit grid connection when a unit is in a shutdown state, and verifying an isolated network threshold value, an isolated network dead zone, a deflector action threshold value and the like by applying a sine wave frequency signal to the frequency side of a speed regulator unit; 2, a no-load simulation isolated network test: forcing a grid-connected signal at a speed regulator side when a unit is in a no-load state, enabling the unit to enter an isolated network mode by manually operating the opening degree of a spray needle, and verifying the rationality of isolated network parameters of a speed regulation system; 3, a load shedding simulation isolated network test is carried out, a unit grid-connected belt has more than 30% of rated load, load shedding is carried out under a speed regulator side forced grid-connected signal and grid-connected state, and dynamic verification of isolated network parameters of the impact type unit is realized. The verification authenticity of the isolated network regulation capability of the impact unit is ensured, and the test difficulty and risk are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of isolated grid control of hydropower units, and in particular relates to an isolated grid regulation performance test method for an impulse hydropower unit. Background Art

[0002] The impulse units have high operating heads and are the main power source at the end of some remote mountainous power grids. The grid structure of regional power grids that are mainly connected by long chains is relatively weak, and the installed capacity of hydropower units in the region is far higher than the total load of the regional power grid. If the regional power grid is disconnected from the main grid due to a fault and forms a regional isolated grid, the high frequency problem of the isolated grid will be prominent.

[0003] Setting reasonable isolated grid PID parameters, isolated grid dead zone, isolated grid threshold and other parameters in isolated grid mode of impulse units is crucial to stabilize the isolated grid frequency and improve the isolated grid regulation capability of the units. At present, how to verify the regulation effect of isolated grid parameters of impulse units has always been a problem to be solved. If we start from the actual project, we can artificially adjust the transmission lines of the power station through grid dispatching to create the conditions for regional isolated grid, but the test cost is too high and the test risk is too high, so this method is generally not adopted; while test equipment such as online isolated grid simulators simulate the adjustment of isolated grid parameters of units by sending frequency signals instead of the actual frequency of the units, and cannot realize the scenario where the units actually operate in isolated grid mode and participate in frequency regulation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for testing the isolated grid regulation performance of an impulse hydropower unit in order to address the problems in the technical background that the test cost of measuring an impulse unit in a regional isolated grid is too high and the risk is too great, and the test of an online isolated grid simulator fails to realize the actual operation of the unit in the isolated grid mode to participate in frequency regulation. The method ensures the authenticity of the verification of the isolated grid regulation capability of the impulse unit and reduces the difficulty and risk of the test.

[0005] The test method of the present invention includes: 1. Static test, simulating the grid connection of the unit when the unit is in shutdown state, and verifying the isolated grid threshold, isolated grid dead zone, deflector action threshold, etc. by applying a sinusoidal wave frequency signal to the frequency side of the speed governor unit; 2. No-load simulated isolated grid test, when the unit is in no-load state, a grid connection signal is forced on the speed governor side, and the unit enters the isolated grid mode by manually operating the needle opening to verify the rationality of the isolated grid parameters of the speed control system; 3. Load shedding simulated isolated grid test, the unit is grid-connected with more than 30% of the rated load, a grid connection signal is forced on the speed governor side, and load shedding is implemented in the grid-connected state to realize dynamic verification of the isolated grid parameters of the impact type unit.

[0006] The specific technical scheme of the present invention is: A method for testing the isolated grid regulation performance of an impulse hydropower unit comprises the following steps: Step 1: Connect the injection needle opening signal, active power signal, deflector action and reset signal, and unit frequency signal of the impact type hydropower unit to the speed control system tester, which is used for measuring analog quantity signals (injector opening signal, active power signal), switch quantity signals (deflector action and reset signal), and unit frequency signal and output; Step 2, static test of the unit: conduct verification tests on the isolated grid threshold, isolated grid frequency dead zone, isolated grid control parameters, etc. of the impulse hydropower unit. The isolated grid threshold and isolated grid dead zone meet the requirements of the regulations, and the isolated grid control parameters meet the requirements of isolated grid regulation. Step 3, static deflector test of the unit: disconnect the frequency terminal of the speed governor unit, and apply a sine wave frequency signal with an amplitude of ±0.1-±3.0Hz and a period of 10-100s to the frequency side of the speed governor unit of the impulse hydropower unit through the speed control system tester to monitor the deflector action, including the deflector action threshold and the deflector reset delay lock time; Step 4, no-load simulated isolated grid test of the unit: When the unit is in no-load operation, short-circuit the grid-connected signal line of the speed control system, manually increase or decrease the nozzle opening, so that the unit frequency exceeds the isolated grid threshold, and the unit enters the isolated grid mode; then continue to manually increase or decrease the nozzle opening, and immediately switch to automatic when the unit frequency rises to 52Hz or drops to 48Hz, monitor the process of the speed control system adjusting the unit frequency to 50Hz, and verify the rationality of the isolated grid parameter settings of the speed control system; Step 5, unit load shedding simulation isolated grid test: the unit is connected to the grid and runs with 30% rated load, the speed control system grid-connected signal line is short-circuited, and then the generator output circuit breaker is disconnected to confirm that the maximum frequency amplitude reaches the threshold condition for entering the isolated grid after the unit sheds 30% rated load, and the speed control system enters the isolated grid mode for frequency adjustment, and the speed and stability meet the requirements of the regulations.

[0007] The static test described in step 2 refers to the unit shutdown state, the water inlet valve is closed, the speed regulator unit frequency terminal is disconnected, the speed regulation system grid-connected signal line is short-circuited, and the speed regulation system tester is used to provide the unit speed regulator with a frequency output signal amplitude of ±0.1-±3.0Hz and a period of 10-100s. The speed regulator action logic and actual action signal output are monitored to see if they are correct.

[0008] The isolated network threshold in step 2 refers to the frequency threshold for other control modes (such as primary frequency modulation mode, large network mode, etc.) to enter the isolated network mode. If the frequency threshold is set to ±0.5Hz, when the frequency exceeds the range of 50±0.5Hz, the speed regulation system automatically enters the isolated network mode and calls the isolated network adjustment parameters. Generally, the isolated network threshold is set to ±0.5Hz; The isolated grid frequency dead zone described in step 2 refers to the manually set frequency dead zone. If the isolated grid frequency dead zone is set to ±0.1Hz, after the unit enters the isolated grid mode, the speed control system will not adjust when the unit frequency changes within 49.9Hz-50.1Hz.

[0009] The deflector reset delay lockout time described in step 3 means that after the unit's deflector is actuated, when the frequency drops to the deflector reset value, the deflector will not reset immediately but will reset after a certain delay. This lockout time is to protect the impulse unit from frequency oscillation caused by frequent deflector action, but too long a lockout time will affect the speed of isolated grid regulation of the impulse unit.

[0010] Furthermore, a sinusoidal frequency signal with an amplitude of ±0.1-±3.0Hz and a period of 10-100s is applied to the frequency side of the speed regulator of the impulse hydropower unit through the speed regulation system tester, such as Figure 2 As shown, at this time, the deflector will make a logical judgment based on the frequency change. If the frequency exceeds the deflector action threshold ±2Hz, the frequency rises to above 52Hz, the deflector will act, deflecting the water flow from the nozzle to the runner, and quickly reducing the unit frequency; when the frequency drops below 48Hz, the deflector will reset, restore the water flow from the nozzle to the runner, and quickly increase the unit frequency. The periodic sinusoidal frequency signal is closer to the frequency oscillation of the unit in the actual isolated grid state than the traditional step frequency signal, which can accurately detect the rationality of the setting of the deflector action threshold and reset delay lock time, and verify the deflector action logic.

[0011] The unit no-load simulated isolated grid test described in step 4 means that the unit is in a no-load frequency mode and is adjusted using no-load parameters.

[0012] Furthermore, by short-circuiting the grid-connected signal in the speed governor, the speed governor is forced to enter the grid-connected operation state, simulating the unit entering a primary frequency regulation or large grid control mode. The actual generator outlet circuit breaker is not closed, and the speed governor is switched to manual operation. The manual increase or decrease of the nozzle opening changes the flow rate of the unit, and the unit frequency gradually deviates from 50Hz. When the unit frequency exceeds the isolated grid threshold of ±0.5Hz, the speed governor enters the isolated grid mode, and the isolated grid parameters are used for adjustment. The nozzle opening is then greatly increased or decreased to cause the unit frequency to deviate by more than ±2Hz. Finally, the speed governor is switched to automatic operation to simulate the large fluctuation of the grid frequency in an isolated grid environment, and verify the rationality of the isolated grid parameters and the deflector action threshold settings of the speed governor during the process of adjusting the unit frequency to 50Hz.

[0013] The unit load shedding simulation grid-connected test described in step 5 refers to the unit entering a primary frequency regulation or large grid control mode, the actual generator outlet circuit breaker is closed, the speed regulation system grid-connected signal is short-circuited, the generator outlet circuit breaker is disconnected, and the unit sheds 30% of the rated load. At this time, the speed regulation system grid-connected signal is short-circuited, and the speed governor is still in the grid-connected operating state, once again verifying the rationality of the speed governor grid-connected parameters and the deflector action threshold settings during the unit frequency adjustment to 50Hz.

[0014] The procedure described in step 5 requires that the speed requirement is that the attenuation of the frequency change of the isolated network regulation is ≤30% (the ratio of the second speed deviation peak with the same sign as the initial deviation to the initial deviation peak), and the stability requirement is that the stabilization time of the isolated network regulation frequency is ≤60s.

[0015] The present invention proposes a test method for the isolated grid regulation performance of an impact hydropower unit, which fills the gap that the isolated grid parameters of the impact unit cannot be dynamically verified on a real machine; by applying a sinusoidal frequency signal to the frequency side of the speed regulator unit of the impact hydropower unit, the frequency oscillation of the unit in the real isolated grid state is simulated, and the rationality of the setting of the deflector action threshold and the reset delay lock time can be accurately detected, and the deflector action logic can be verified; by forcing a grid-connected signal on the speed regulator side, manually operating the needle opening in the no-load state of the impact unit, and implementing load shedding in the grid-connected state, the dynamic verification of the isolated grid parameters of the impact unit is realized, which not only ensures the authenticity of the verification of the isolated grid regulation capability of the impact unit, but also reduces the difficulty and risk of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of a method for testing the isolated grid regulation performance of an impulse hydroelectric generator set.

[0017] Figure 2 This is a block diagram of the impulse unit model of the present invention, in which f ref is the given frequency; f g is the unit frequency.

[0018] Figure 3 This is a curve diagram of the isolated network threshold test in an example of the present invention.

[0019] Figure 4 It is a test curve diagram of the deflector action threshold and reset delay locking time in an example of the present invention.

[0020] Figure 5 This is a curve chart of the no-load simulated isolated grid test of the unit in the example of the present invention.

[0021] Figure 6 This is a curve diagram of load shedding simulation isolated grid test of the unit in the example of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the examples. It will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer is not specified in the instruments used, they are all conventional products that can be purchased. Example

[0023] like Figure 1 As shown, a method for testing the isolated grid regulation performance of an impulse hydropower unit comprises the following steps: Step 1: Connect the injection needle opening signal, active power signal, deflector action and reset signal, and unit frequency signal of the impact type hydropower unit to the speed control system tester (the tester is a device for realizing field tests, existing technology). The speed control system tester is used for measuring analog quantity signals (injection needle opening signal, active power signal), switching quantity signals (deflector action and reset signal), and unit frequency signal measurement and output. The tester is a device for realizing field tests.

[0024] Step 2: Static test of the unit: Verification tests are carried out on the isolated grid threshold, isolated grid frequency dead zone, and isolated grid control parameters of the impulse hydropower unit. The isolated grid threshold and isolated grid dead zone meet the requirements of the regulations, and the isolated grid control parameters meet the requirements of isolated grid regulation.

[0025] Step 3, static deflector test of the unit: disconnect the frequency terminal of the speed regulator unit, and apply a sinusoidal frequency signal with an amplitude of ±0.1-±3.0Hz and a period of 10-100s to the frequency side of the speed regulator unit of the impulse hydropower unit through the speed regulation system tester to monitor the deflector action, including the deflector action threshold and the deflector return delay lock time.

[0026] Step 4, no-load simulated isolated grid test of the unit: When the unit is in no-load operation, short-circuit the grid-connected signal line of the speed control system, manually increase or decrease the nozzle opening, so that the unit frequency exceeds the isolated grid threshold, and the unit enters the isolated grid mode; then continue to manually increase or decrease the nozzle opening, and immediately switch to automatic when the unit frequency rises to 52Hz or drops to 48Hz, monitor the process of the speed control system adjusting the unit frequency to 50Hz, and verify the rationality of the isolated grid parameter settings of the speed control system.

[0027] Step 5, unit load shedding simulation isolated grid test: the unit is connected to the grid and runs with 30% rated load, the speed control system grid-connected signal line is short-circuited, and then the generator output circuit breaker is disconnected to confirm that the maximum frequency amplitude reaches the threshold condition for entering the isolated grid after the unit sheds 30% rated load, and the speed control system enters the isolated grid mode for frequency adjustment, and the speed and stability meet the requirements of the regulations.

[0028] The static test described in step 2 refers to the unit shutdown state, the water inlet valve is closed, the speed regulator unit frequency terminal is disconnected, the speed regulation system grid-connected signal line is short-circuited, and the speed regulation system tester is used to provide the unit speed regulator with a frequency output signal amplitude of ±0.1-±3.0Hz and a period of 10-100s. The speed regulator action logic and actual action signal output are monitored to see if they are correct.

[0029] The isolated network threshold in step 2 refers to the frequency threshold for other control modes (such as primary frequency modulation mode, large network mode, etc.) to enter the isolated network mode. If the frequency threshold is set to ±0.5Hz, when the frequency exceeds the range of 50±0.5Hz, the speed regulation system automatically enters the isolated network mode and calls the isolated network adjustment parameters. Generally, the isolated network threshold is set to ±0.5Hz; The isolated grid frequency dead zone described in step 2 refers to the manually set frequency dead zone. If the isolated grid frequency dead zone is set to ±0.1Hz, after the unit enters the isolated grid mode, the speed control system will not adjust when the unit frequency changes within 49.9Hz-50.1Hz.

[0030] The deflector reset delay lockout time described in step 3 means that after the unit's deflector is actuated, when the frequency drops to the deflector reset value, the deflector will not reset immediately but will reset after a certain delay. This lockout time is to protect the impulse unit from frequency oscillation caused by frequent deflector action, but too long a lockout time will affect the speed of isolated grid regulation of the impulse unit.

[0031] A sine wave frequency signal with an amplitude of ±0.1-±3.0Hz and a period of 10-100s is applied to the frequency side of the speed regulator of the impulse hydropower unit through the speed regulation system tester. Figure 2 As shown, at this time, the deflector will make a logical judgment based on the frequency change. If the frequency exceeds the deflector action threshold ±2Hz, the frequency rises to above 52Hz, the deflector will act, deflecting the water flow from the nozzle to the runner, and quickly reducing the unit frequency; when the frequency drops below 48Hz, the deflector will reset, restore the water flow from the nozzle to the runner, and quickly increase the unit frequency. The periodic sinusoidal frequency signal is closer to the frequency oscillation of the unit in the actual isolated grid state than the traditional step frequency signal, which can accurately detect the rationality of the setting of the deflector action threshold and reset delay lock time, and verify the deflector action logic.

[0032] The unit no-load simulated isolated grid test described in step 4 means that the unit is in a no-load frequency mode and is adjusted using no-load parameters.

[0033] By short-circuiting the grid-connected signal on the speed governor, the speed governor is forced to enter the grid-connected operation state, simulating the unit entering a primary frequency regulation or large grid control mode. The actual generator outlet circuit breaker is not closed, and the speed governor is switched to manual operation. The manual increase or decrease of the nozzle opening changes the unit flow rate, and the unit frequency gradually deviates from 50Hz. When the unit frequency exceeds the isolated grid threshold of ±0.5Hz, the speed governor enters the isolated grid mode, and the isolated grid parameters are used for adjustment. The nozzle opening is then greatly increased or decreased to cause the unit frequency to deviate by more than ±2Hz. Finally, the speed governor is switched to automatic operation to simulate the large fluctuation of the grid frequency in an isolated grid environment, and verify the rationality of the isolated grid parameters and the deflector action threshold settings of the speed governor during the process of adjusting the unit frequency to 50Hz.

[0034] The unit load shedding simulation grid-connected test described in step 5 refers to the unit entering a primary frequency regulation or large grid control mode, the actual generator outlet circuit breaker is closed, the speed regulation system grid-connected signal is short-circuited, the generator outlet circuit breaker is disconnected, and the unit sheds 30% of the rated load. At this time, the speed regulation system grid-connected signal is short-circuited, and the speed governor is still in the grid-connected operating state, once again verifying the rationality of the speed governor grid-connected parameters and the deflector action threshold settings during the unit frequency adjustment to 50Hz.

[0035] The procedure described in step 5 requires that the speed requirement is that the attenuation of the frequency change of the isolated network regulation is ≤30% (the ratio of the second speed deviation peak with the same sign as the initial deviation to the initial deviation peak), and the stability requirement is that the stabilization time of the isolated network regulation frequency is ≤60s.

[0036] Application examples:

[0037] Unit 1 of a power station is of impulse type. The water supply system adopts a one-pipe two-machine water diversion method. The rated active power is 6300kW, the rated head is 435.5m, the rated speed is 600r / min, and the rated flow is 1.9m 3 / s; The primary frequency regulation parameters of the unit are: bt=20%, Td=1s, Tn=0s, primary frequency regulation dead zone ±0.05Hz, bp=4%; The unit's isolated network parameters are set to: bt=55%, Td=10s, Tn=0.2s, isolated network threshold ±0.5Hz, isolated network dead zone ±0.2Hz, bp=1%; The deflector action logic: close the deflector at 52Hz and open the deflector at 50.1Hz.

[0038] Step 1: Connect the nozzle opening signal, active power signal, deflector action and reset signal, and unit frequency signal to the speed control system tester.

[0039] Step 2: The unit is in shutdown state, the water inlet valve is closed, and the governor unit frequency feedback f is disconnected g , short-circuit the grid-connected signal line of the speed control system, such as Figure 2As shown in the figure, the speed control system tester provides a sine wave frequency signal with a frequency input amplitude of ±0.6Hz and a period of 100s to the unit speed controller, such as Figure 3 As shown, when the frequency difference exceeds 0.5Hz, the unit speed governor enters the isolated grid mode and switches to the isolated grid parameters. The isolated grid threshold is actually measured to be ±0.5Hz. The speed governor exits the isolated grid mode and enters the primary frequency modulation mode 30s after the frequency is adjusted to 50Hz. When the frequency is restored to low frequency, the spray needle moves quickly.

[0040] Figure 2 Medium ref is the given frequency; f g is the unit frequency.

[0041] Step 3: If Figure 2 As shown in the figure, a sine wave frequency signal with an amplitude of ±2.6Hz and a period of 100s is applied to the frequency side of the speed regulator of the impulse hydropower unit through the speed regulation system tester. The speed regulator makes a logical judgment based on the frequency change, such as Figure 4 The periodic sinusoidal frequency signal shown is closer to the frequency oscillation of the unit in the real isolated grid state than the traditional step frequency signal. It can accurately detect that the deflector is closed when the frequency rises to 52Hz and the deflector is reset when the frequency drops to 50.1Hz. The reset delay lock time is less than 50s. The current deflector action and reset logic has too frequent needle action. The deflector action logic is modified to: close the deflector at 53Hz and open the deflector at 52.6Hz.

[0042] Step 4: When the unit is in no-load operation, the speed governor is forced to enter the grid-connected operation state by short-circuiting the grid-connected signal on the speed governor, simulating the unit entering the primary frequency regulation mode. The actual generator outlet circuit breaker is not closed, and the speed governor is switched to manual operation. The manual reduction of the nozzle opening causes the unit flow to change, and the unit frequency gradually deviates from 50Hz. When the unit frequency exceeds the isolated grid threshold of ±0.5Hz, the speed governor enters the isolated grid mode, uses the isolated grid parameters for adjustment, and then significantly reduces the nozzle opening to cause the unit frequency to deviate by more than ±2Hz. Finally, the speed governor is switched to automatic operation to simulate the large fluctuation of the grid frequency in the isolated grid environment, and verify the rationality of the isolated grid parameters and the deflector action threshold settings of the speed governor during the unit frequency adjustment to 50Hz. The test curve is as follows Figure 5 As shown, from Figure 5 It can be seen that when the unit adopts the current isolated grid parameters and the modified deflector action threshold, the unit can be adjusted to 50Hz more quickly.

[0043] Step 5: The unit is connected to the grid with 30% rated load. The unit is in primary frequency control mode. The speed control system grid signal line is short-circuited, and then the generator output circuit breaker is disconnected. The unit actually sheds load, but because the speed control system grid signal line is short-circuited, the speed governor is still in grid operation. The recording curve of the entire test process is as follows: Figure 6 As shown in the figure, after the unit sheds 30% of the rated load, the frequency reaches a maximum of 56.1Hz, reaching the threshold condition for entering the isolated grid. During the process of the unit shedding the load and the frequency rising, the unit has entered the isolated grid mode. When the frequency rises to 53Hz, the folding device is closed, and when the frequency drops to 52.6Hz, the folding device is opened. The attenuation of the isolated grid regulation frequency change is 3% (the ratio of the second speed deviation peak with the same sign as the initial deviation to the initial deviation peak), and the isolated grid regulation frequency stabilization time is about 55s.

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A test method for isolated grid regulation performance of impulse hydropower units, characterized in that: The following steps are involved: Step 1: Connect the injection needle opening signal, active power signal, deflector action and reset signal, and unit frequency signal of the impact type hydropower unit to the speed control system tester, which is used for analog signal measurement---injection needle opening signal, active power signal, switch signal measurement---deflector action and reset signal, unit frequency signal measurement and output; Step 2, static test of the unit: conduct verification tests on the isolated grid threshold, isolated grid frequency dead zone, and isolated grid control parameters of the impulse hydropower unit. The isolated grid threshold and isolated grid dead zone meet the requirements of the regulations, and the isolated grid control parameters meet the requirements of isolated grid regulation. Step 3, static deflector test of the unit: disconnect the frequency terminal of the speed governor unit, and apply a sine wave frequency signal with an amplitude of ±0.1-±3.0Hz and a period of 10-100s to the frequency side of the speed governor unit of the impulse hydropower unit through the speed control system tester to monitor the deflector action, including the deflector action threshold and the deflector reset delay lock time; Step 4, no-load simulated isolated grid test of the unit: when the unit is in no-load operation, short-circuit the grid-connected signal line of the speed control system, manually increase or decrease the nozzle opening, so that the unit frequency exceeds the isolated grid threshold, and the unit enters the isolated grid mode; then continue to manually increase or decrease the nozzle opening, and immediately switch to automatic when the unit frequency rises to 52Hz or drops to 48Hz, monitor the process of the speed control system adjusting the unit frequency to 50Hz, and verify the rationality of the isolated grid parameter settings of the speed control system; Step 5, unit load shedding simulation isolated grid test: the unit is connected to the grid and runs with 30% rated load, the speed control system grid-connected signal line is short-circuited, and then the generator output circuit breaker is disconnected to confirm that the maximum frequency amplitude reaches the threshold condition for entering the isolated grid after the unit sheds 30% rated load, and the speed control system enters the isolated grid mode for frequency adjustment, and the speed and stability meet the requirements of the regulations.

2. The test method for isolated grid regulation performance of impulse hydropower units according to claim 1 is characterized in that: The static test described in step 2 refers to the unit shutdown state, the water inlet valve is closed, the speed regulator unit frequency terminal is disconnected, the speed regulation system grid-connected signal line is short-circuited, and the speed regulation system tester is used to provide the unit speed regulator with a frequency output signal amplitude of ±0.1-±3.0Hz and a period of 10-100s. The speed regulator action logic and actual action signal output are monitored to see if they are correct.

3. The test method for isolated grid regulation performance of impulse hydropower unit according to claim 1 is characterized in that: The isolated network threshold described in step 2 refers to the frequency threshold for other control modes to enter the isolated network mode. If the frequency threshold is set to ±0.5Hz, when the frequency exceeds the range of 50±0.5Hz, the speed regulation system automatically enters the isolated network mode, calls the isolated network adjustment parameters, and sets the isolated network threshold to ±0.5Hz.

4. The method for testing the isolated grid regulation performance of an impact hydropower unit according to claim 1 is characterized in that: The isolated grid frequency dead zone described in step 2 refers to the manually set frequency dead zone. If the isolated grid frequency dead zone is set to ±0.1Hz, after the unit enters the isolated grid mode, the speed control system will not adjust when the unit frequency changes within 49.9Hz-50.1Hz.

5. The test method for isolated grid regulation performance of impulse hydropower unit according to claim 1 is characterized in that: The deflector reset delay lockout time described in step 3 means that after the unit's deflector is actuated, when the frequency drops to the deflector reset value, the deflector will not reset immediately but will reset after a certain delay. This lockout time is to protect the impulse unit from frequency oscillation caused by frequent deflector action, but too long a lockout time will affect the speed of isolated grid regulation of the impulse unit.

6. The test method for isolated grid regulation performance of impulse hydropower unit according to claim 1 is characterized in that: The unit no-load simulated isolated grid test described in step 4 means that the unit is in a no-load frequency mode and is adjusted using no-load parameters.

7. The test method for isolated grid regulation performance of impulse hydropower unit according to claim 1 is characterized by: The unit load shedding simulation grid-connected test described in step 5 refers to the unit entering a primary frequency regulation or large grid control mode, the actual generator outlet circuit breaker is closed, the speed regulation system grid-connected signal is short-circuited, the generator outlet circuit breaker is disconnected, and the unit sheds 30% of the rated load. At this time, the speed regulation system grid-connected signal is short-circuited, and the speed governor is still in the grid-connected operating state, once again verifying the rationality of the speed governor grid-connected parameters and the deflector action threshold settings during the unit frequency adjustment to 50Hz.

8. The method for testing the isolated grid regulation performance of an impulse hydroelectric generator set according to claim 1 is characterized in that: The regulations described in step 5 require that the speed requirement is that the frequency change attenuation of the isolated grid regulation is ≤30%, and the stability requirement is that the stabilization time of the isolated grid regulation frequency is ≤60s.

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