Joint adjustment method for dual-machine frequency stabilization of small power grid speed regulator

Abstract

A method for coordinating dual-machine frequency stabilization of a small power grid speed regulator includes the following steps: 1) the speed regulator determines whether an isolated grid phenomenon occurs by detecting the connection status of the turbine unit in the hydropower station and the power grid; 2) when an isolated grid occurs, frequency adjustment is performed; 3) the upstream and downstream water level difference and the no-load guide vane opening are monitored in real time, and the no-load guide vane opening is adjusted according to the range of the water level difference; 4) the guide vane opening of the auxiliary regulating unit is adjusted according to the active power of the auxiliary regulating unit and the main regulating unit; 5) the delay time and the guide vane opening are adjusted based on the existing set value according to the range of the water head. The present invention uses the main speed regulator to perform frequency regulation and load fluctuation adjustment, and the auxiliary speed regulator to selectively adjust, so that the two units can work in different areas when the frequency of the small power grid is unstable and fluctuates frequently, effectively eliminating the interference problem between them, and at the same time monitoring the output power of the auxiliary speed regulator to ensure that the unit does not enter the leading phase state.

Description

Technical Field

[0001] The present invention relates to the technical field of small-scale power grid control, and in particular to a joint control method for dual-machine frequency stabilization of a small-scale power grid speed regulator. Background Art

[0002] After being incorporated into the large power grid, small hydropower stations generally use a closed-loop control method for opening regulation to ensure the stability of output active power. Before being incorporated into the large power grid, they use a closed-loop control method for frequency regulation to ensure frequency stability.

[0003] Small power stations along rivers in towns and villages have a single power supply method and a single grid structure. During grid failures or substation reconstruction, small power station units may provide long-term power supply to a small number of surrounding users.

[0004] The electricity usage is as attached Figure 1 In this case, the load changes greatly and is difficult to adjust, as follows:

[0005] 1. The electricity demand of surrounding users is irregular and changes frequently, with many sudden rises and falls, resulting in unstable and frequent fluctuations in the frequency of the small power grid.

[0006] 2. Due to the release of water from the hydraulic hub, the water level downstream changes greatly, and the change in the unit's generating head is greatly affected. Similarly, when the guide vane opening is 11%, the active power may be positive 100kw or negative 100kw.

[0007] 3. There is a 200kw high-power water pump nearby. The water pump has a great impact on the small power grid when it is put into operation and shut down, and the frequency fluctuates greatly. When it is put into operation, the two units will be pulled up at the same time. When it is shut down, sometimes the two units that adjust faster will become leading-phase operation, and manual operation is required to restore it.

[0008] Fourth, when two generators are connected to the grid simultaneously, due to different governor shaft clearances, mechanical adjustment performance, and electrical control parameters, they can interfere with each other and compete for load. This can even lead to situations where one generator's guide vanes are opening while the other's are decreasing. This can ultimately lead to small grid system shocks, unit disconnection, and other accidents.

[0009] Therefore, it is necessary to solve the problem that the power load of surrounding users fluctuates greatly, with many sudden rises and falls. It reaches 500kw during peak periods and only 50kw during low periods. After the water head changes, the rated no-load opening of the guide vane will change accordingly. When two units are started at the same time, one unit will often run in advance, reducing the safety and stability of the unit. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a joint adjustment method for dual-machine frequency stabilization of a small power grid speed regulator. The main frequency adjustment and load fluctuation adjustment are performed by the current main speed regulator, and the auxiliary speed regulator does not adjust when the adjustment range does not exceed the line. The two units can work in different areas when the frequency of the small power grid is unstable and fluctuates frequently, effectively eliminating the interference problem between them. At the same time, the output power of the auxiliary speed regulator is monitored, and fine-tuning is performed when necessary to ensure that the unit does not enter the leading phase state.

[0011] To solve the above technical problems, the technical solution adopted by the present invention is: a method for joint frequency stabilization of dual-machine speed regulators in a small power grid, comprising the following steps:

[0012] 1) The speed governor detects the connection status between the turbine unit in the hydropower station and the power grid to determine whether there is an isolated grid phenomenon;

[0013] 2) When an isolated grid occurs, the two speed governors are divided into the main regulating unit and the auxiliary regulating unit according to the control handles on the panel. If both handles are in the main regulating unit or both are in the auxiliary regulating unit, Unit 1 is defaulted to be the main regulating unit and Unit 2 is defaulted to be the auxiliary regulating unit, and frequency regulation is performed on this basis;

[0014] 3) Real-time monitoring of the upstream and downstream water level difference and the no-load guide vane opening, and adjustment of the no-load guide vane opening according to the range of the water level difference;

[0015] 4) Adjust the guide vane opening of the auxiliary regulating unit according to the active power of the auxiliary regulating unit and the main regulating unit;

[0016] 5) According to the water head range, adjust the delay time and guide vane opening based on the existing set values.

[0017] In a preferred solution, in step 2), the auxiliary adjustment unit automatically changes the relevant parameter setting values ​​of the guide vane minimum opening 5%, the guide vane maximum opening 25%, and the frequency dead zone 0.5HZ;

[0018] The main regulating unit automatically changes the relevant parameter settings of the guide vane minimum opening 2%, the guide vane maximum opening 40%, and the frequency dead zone 0.2HZ.

[0019] In a preferred solution, in the auxiliary regulating unit and the main regulating unit, the amplification coefficient of the guide vane opening direction is increased by 20, the amplification coefficient of the guide vane closing direction is increased by 20, and the guide vane regulation width pulse is increased by 20.

[0020] In a preferred solution, in step 4), when the active power of the auxiliary regulating unit is negative and less than 100 kW, the guide vane opening of the auxiliary regulating unit is increased by 0.3%-0.8% every 5-10 minutes;

[0021] When the active power of the auxiliary regulating unit is negative and greater than 100kw and less than 300kw, the guide vane opening of the auxiliary regulating unit will be increased by 0.3%-0.8% every 1-5 minutes of delay;

[0022] When the active power of the auxiliary regulating unit is negative and greater than 300kw, the guide vane opening of the auxiliary regulating unit will be increased by 0.3%-0.8% for every 15 seconds to 1 minute delay;

[0023] When the active power of the main regulating unit is negative and the active power of the auxiliary regulating unit is positive and greater than 50kW and less than 100kW, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% every 5-10 minutes;

[0024] When the active power of the main regulating unit is negative and the power of the auxiliary regulating unit is positive and greater than 100kw and less than 300kw, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% every 1-5 minutes of delay;

[0025] When the active power of the main regulating unit is negative and the power of the auxiliary regulating unit is positive and greater than 300kw, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% for every delay of 15 seconds to 1 minute.

[0026] In a preferred solution, in step 5), when the water head is in a small interval, the delay time is reduced by 5-30 seconds based on the existing set value, and the opening change is increased by 0.1% based on the existing set value;

[0027] When the water head is in a large range, the delay time increases by 5-30 seconds based on the existing setting value, and the opening change decreases by 0.1% based on the existing setting value.

[0028] The present invention provides a method for coordinating dual-machine frequency stabilization of a small power grid speed regulator. By adopting the above method, the following beneficial effects are achieved:

[0029] (1) By monitoring the occurrence of arcing in the power grid and adjusting the frequency of the two units according to the arcing, the system avoids accidents such as grid system oscillation and unit disconnection and power outage caused by the simultaneous operation of two generators in the grid, and at the same time meets the irregular power demand of surrounding users, solving the problem of unstable and frequent frequency fluctuations in small power grids;

[0030] (2) The guide vanes of the auxiliary regulating unit are adjusted to different openings according to the active power values ​​of the main regulating unit and the auxiliary regulating unit, which solves the problem that the water pump has a large impact on the small power grid at the moment of commissioning and shutting down, and the frequency fluctuates greatly. When the two units are put into operation, they will be pulled up at the same time. When they are shut down, sometimes the faster-adjusted unit will turn into leading phase operation, which requires manual operation to recover.

[0031] (3) By real-time monitoring of the upstream and downstream water level difference and the no-load guide vane opening and adjusting the no-load guide vane opening according to the range of the water level difference, the impact of the increased downstream water level changes caused by the water conservancy project's waterproofing is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the accompanying drawings and examples:

[0033] Figure 1 This is a simplified diagram of the power grid system in which the present invention is located.

[0034] Figure 2 It is a flowchart of the present invention. DETAILED DESCRIPTION

[0035] Example 1:

[0036] A method for coordinating dual-machine frequency stabilization of a small power grid speed regulator comprises the following steps:

[0037] 1) The speed governor detects the connection status between the turbine unit in the hydropower station and the power grid to determine whether there is an isolated grid phenomenon;

[0038] 2) When an isolated grid occurs, the two speed governors are divided into the main regulating unit and the auxiliary regulating unit according to the control handles on the panel. If both handles are in the main regulating unit or both are in the auxiliary regulating unit, Unit 1 is defaulted to be the main regulating unit and Unit 2 is defaulted to be the auxiliary regulating unit, and frequency regulation is performed on this basis;

[0039] 3) Real-time monitoring of the upstream and downstream water level difference and the no-load guide vane opening, and adjustment of the no-load guide vane opening according to the range of the water level difference;

[0040] 4) Adjust the guide vane opening of the auxiliary regulating unit according to the active power of the auxiliary regulating unit and the main regulating unit;

[0041] 5) According to the water head range, adjust the delay time and guide vane opening based on the existing set values.

[0042] In step 2), the auxiliary adjustment unit automatically changes the relevant parameter settings of the guide vane minimum opening 5%, the guide vane maximum opening 25%, and the frequency dead zone 0.5HZ;

[0043] The main regulating unit automatically changes the relevant parameter settings of the guide vane minimum opening 2%, the guide vane maximum opening 40%, and the frequency dead zone 0.2HZ;

[0044] In the auxiliary regulating unit and the main regulating unit, the amplification coefficient of the guide vane opening direction is increased by 20, the amplification coefficient of the guide vane closing direction is increased by 20, and the guide vane regulation width pulse is increased by 20.

[0045] Example 2:

[0046] As attached Figure 2 In step 4), when the active power of the auxiliary regulating unit is negative and less than 100 kW, the guide vane opening of the auxiliary regulating unit is increased by 0.3%-0.8% every 5-10 minutes;

[0047] When the active power of the auxiliary regulating unit is negative and greater than 100kw and less than 300kw, the guide vane opening of the auxiliary regulating unit will be increased by 0.3%-0.8% every 1-5 minutes of delay;

[0048] When the active power of the auxiliary regulating unit is negative and greater than 300kw, the guide vane opening of the auxiliary regulating unit will be increased by 0.3%-0.8% for every 15 seconds to 1 minute delay;

[0049] When the active power of the main regulating unit is negative and the active power of the auxiliary regulating unit is positive and greater than 50kW and less than 100kW, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% every 5-10 minutes;

[0050] When the active power of the main regulating unit is negative and the power of the auxiliary regulating unit is positive and greater than 100kw and less than 300kw, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% every 1-5 minutes of delay;

[0051] When the active power of the main regulating unit is negative and the power of the auxiliary regulating unit is positive and greater than 300kw, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% for every delay of 15 seconds to 1 minute.

[0052] Example 3:

[0053] The range of the water level difference in step 3) is adjusted according to the following table:

[0054] Real-time monitoring of the upstream and downstream water level difference and the no-load guide vane opening changes according to the table below, with linear changes between every two sets of data;

[0055]

[0056] Among them, A and B are low head intervals;

[0057] C and D are high head intervals.

[0058] Based on the above table, in step 5), when the water head is in the low range (i.e., when the water level is between ranges A or B), the delay time is reduced by 5-30 seconds based on the existing setting value, and the opening change is increased by 0.1% based on the existing setting value;

[0059] When the water head is in the high range (i.e., when the water level is between ranges C or D), the delay time increases by 5-30 seconds based on the existing setting value, and the opening change decreases by 0.1% based on the existing setting value.

Claims

1. A method for joint frequency stabilization of dual-machine speed regulators in a small power grid, characterized in that The following steps are involved: 1) The speed governor detects the connection status between the turbine unit in the hydropower station and the power grid to determine whether there is an isolated grid phenomenon; 2) When an isolated grid occurs, the two speed governors are divided into the main regulating unit and the auxiliary regulating unit according to the control handles on the panel. If both handles are in the main regulating unit or both are in the auxiliary regulating unit, Unit 1 is defaulted to be the main regulating unit and Unit 2 is defaulted to be the auxiliary regulating unit, and frequency regulation is performed on this basis; 3) Real-time monitoring of the upstream and downstream water level difference and the no-load guide vane opening, and adjustment of the no-load guide vane opening according to the range of the water level difference; 4) Adjust the guide vane opening of the auxiliary regulating unit according to the active power of the auxiliary regulating unit and the main regulating unit; 5) According to the water head range, adjust the delay time and guide vane opening based on the existing set values; In step 2), the auxiliary adjustment unit automatically changes the relevant parameter settings of the guide vane minimum opening 5%, the guide vane maximum opening 25%, and the frequency dead zone 0.5HZ; The main regulating unit automatically changes the relevant parameter settings of the guide vane minimum opening 2%, the guide vane maximum opening 40%, and the frequency dead zone 0.2HZ.

2. The method for coordinating dual-machine frequency stabilization of a small power grid speed regulator according to claim 1, characterized in that: In the auxiliary regulating unit and the main regulating unit, the amplification coefficient of the guide vane opening direction is increased by 20, the amplification coefficient of the guide vane closing direction is increased by 20, and the guide vane regulation width pulse is increased by 20.

3. The method for joint frequency stabilization of dual-machine speed regulators in a small power grid according to claim 1, characterized in that: In step 4), when the active power of the auxiliary regulating unit is negative and less than 100 kW, the guide vane opening of the auxiliary regulating unit is increased by 0.3%-0.8% every 5-10 minutes; When the active power of the auxiliary regulating unit is negative and greater than 100kw and less than 300kw, the guide vane opening of the auxiliary regulating unit will be increased by 0.3%-0.8% every 1-5 minutes of delay; When the active power of the auxiliary regulating unit is negative and greater than 300kw, the guide vane opening of the auxiliary regulating unit will be increased by 0.3%-0.8% for every 15 seconds to 1 minute delay; When the active power of the main regulating unit is negative and the active power of the auxiliary regulating unit is positive and greater than 50kW and less than 100kW, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% every 5-10 minutes; When the active power of the main regulating unit is negative and the power of the auxiliary regulating unit is positive and greater than 100kw and less than 300kw, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% every 1-5 minutes of delay; When the active power of the main regulating unit is negative and the power of the auxiliary regulating unit is positive and greater than 300kw, the guide vane opening of the auxiliary regulating unit will be reduced by 0.3%-0.8% for every delay of 15 seconds to 1 minute.

4. The method for coordinating dual-machine frequency stabilization of a small power grid speed regulator according to claim 1 is characterized in that: In step 5), when the water head is in a small interval, the delay time is reduced by 5-30 seconds based on the existing setting value, and the opening change is increased by 0.1% based on the existing setting value; When the water head is in a large range, the delay time increases by 5-30 seconds based on the existing setting value, and the opening change decreases by 0.1% based on the existing setting value.

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