Primary frequency modulation and AGC coordination control method for hydroelectric generating set speed regulator

Abstract

The invention relates to the technical field of electric power, and discloses a primary frequency modulation and AGC coordinated control method for a hydroelectric generating set speed regulator, which judges the operation state of a hydroelectric generating set by combining the power grid frequency, the primary frequency modulation state of a speed regulation system and an AGC control instruction, and selects different regulation modes to carry out power closed-loop regulation on the speed regulator. The problems of low power frequency adjusting capability and the like in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of electric power, in particular to a method for coordinated control of primary frequency regulation and AGC of a speed regulator of a hydropower unit. Background Art

[0002] In recent years, in order to further improve the safety and stability of the power grid, the regional power grid and the main grid have entered an asynchronous interconnected operation mode, that is, the regional power grid and the main grid are connected through a DC circuit. This mode puts forward new requirements for the power-frequency control scheme of the hydro-turbine generator set, that is, it must meet both the stability and the speed of the power-frequency regulation.

[0003] In addition, the continuous large-scale access of new energy sources such as wind power and photovoltaics to the power grid has led to major changes in the characteristics of the power grid. In particular, the rotational inertia has gradually decreased with the access of new energy. The grid side has put forward higher requirements on the power-frequency regulation capability of traditional hydropower units. The hydropower units are required to provide both rapid power response capabilities and effective rotational inertia and avoid low-frequency oscillations induced by negative damping effects. This has put forward higher requirements on the primary frequency regulation and AGC coordinated control of the hydro-turbine generator sets. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed regulator, which solves the problems of low power frequency regulation capability in the prior art.

[0005] The technical solution adopted by the present invention to solve the above problems is:

[0006] A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed regulator combines power grid frequency, primary frequency regulation state of a speed regulation system and AGC control instructions to judge the operating state of the hydropower unit, and selects different regulation modes to perform power closed-loop regulation on the speed regulator.

[0007] As a preferred technical solution, it includes the step of comprehensive selection of control mode: selecting power mode AGC control mode or power mode primary frequency modulation control mode to perform power closed-loop regulation.

[0008] As a preferred technical solution, the basis for comprehensive selection of control methods includes:

[0009] A. When the grid frequency exceeds the primary frequency regulation dead zone, regardless of whether there is a new AGC regulation command issued by the wheel, the power mode primary frequency regulation control method is automatically selected for power closed-loop regulation.

[0010] As a preferred technical solution, the basis for comprehensive selection of control methods includes:

[0011] B. When the grid frequency does not exceed the power dead zone, if there is a new AGC adjustment instruction from the computer monitoring system, the power mode AGC control method will be automatically selected for power closed-loop regulation.

[0012] As a preferred technical solution, the basis for comprehensive selection of control methods includes:

[0013] C. Except for situations A and B, the previous regulation cycle regulation control mode is maintained for power closed-loop regulation.

[0014] As a preferred technical solution, when the power mode AGC control method is used for power closed-loop regulation, the speed governor uses the power mode AGC control method to complete power regulation according to the hydropower unit power control target value Pset issued by the monitoring system, until the regulated unit power enters the power regulation dead zone, and the power closed-loop regulation ends; wherein, the formula for the unit power entering the power regulation dead zone is: |Pset-Pg|≤Pdeadband; wherein, Pset represents the unit AGC given value issued by the computer monitoring system, Pg represents the actual power of the unit, and Pdeadband represents the unit power regulation dead zone.

[0015] As a preferred technical solution, during the power mode AGC control mode adjustment process, if a frequency modulation action is performed, the power mode one-time frequency modulation control mode is automatically entered until the one-time frequency modulation adjustment is completed and the power adjustment is completed.

[0016] As a preferred technical solution, the primary frequency regulation end judgment formula is: |Fgrid-50|≤Fdeadband; wherein, Fgrid represents the grid frequency, and Fdeadband represents the primary frequency regulation dead zone.

[0017] As a preferred technical solution, the power regulation completion judgment formula is: |Pset-Pg|≤Pdeadband; where Pset represents the AGC given value of the unit issued by the computer monitoring system, Pg represents the actual power generated by the unit, and Pdeadband represents the power regulation dead zone of the unit.

[0018] As a preferred technical solution, when the grid frequency does not receive the new AGC adjustment instruction issued by the hydropower station computer monitoring system, the power mode primary frequency regulation control method is adopted by default; if |Pset-Pset_pre|≥P_pa, the power mode AGC control method is automatically entered; where Pset represents the calculation of the current active setting value of the computer monitoring system, and P_pa represents the preset value P_pa.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention optimizes the power starting point of the primary frequency modulation of the generator set from the traditional AGC power setting value of the generator set to the actual power value of the generator set at the moment of the primary frequency modulation action, which is more in line with the theory and also takes into account the actual power deviation and fluctuation;

[0021] (2) The present invention does not affect the normal AGC power regulation and primary frequency regulation functions of the unit in terms of process, and the coordination relationship between AGC regulation and primary frequency regulation meets the requirements of national standards;

[0022] (3) The present invention can effectively enhance the supporting effect of primary frequency regulation on the grid frequency, and improve the contribution of primary frequency regulation and regulation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the process of the present invention;

[0024] Figure 2 This is the flow chart of instantaneous power recording of a frequency modulation action of the speed regulator;

[0025] Figure 3 It is a flow chart for judging the power fluctuation direction of the unit and the primary head action direction;

[0026] Figure 4 It is the unit AGC set value action judgment logic diagram;

[0027] Figure 5 Calculation flow chart for power regulation target of speed regulator;

[0028] Figure 6 This is a schematic diagram of the unit used in the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0030] Example 1

[0031] like Figures 1 to 6 As shown, the present invention discloses a method for coordinated control of primary frequency regulation and AGC under power mode of a hydro-turbine generator set, which comprehensively judges the operating state of the unit through the grid frequency, the speed regulation system control mode, and the power station AGC control instruction, selects different regulation modes, and improves the AGC regulation speed when the primary frequency regulation is not in operation while ensuring the stability of the primary frequency regulation under the asynchronous networking operation mode, thereby improving the power frequency regulation capability on the power supply side and improving the support capability for the power grid.

[0032] A method for coordinated control of primary frequency regulation and AGC in power mode of a hydro-turbine generator set is disclosed, wherein the units adopted include a control mode comprehensive selection process S1 unit, a power mode AGC control process S2 unit, a power mode primary frequency regulation control process S3 unit, and a primary frequency regulation judgment process S4 unit during AGC regulation.

[0033] A further solution is a comprehensive control method selection process S1:

[0034] Control mode comprehensive selection process S1, when the speed control system of the hydro-turbine generator set is connected to the grid in power mode, according to the primary frequency regulation state of the speed control system and the AGC regulation instruction state of the unit, it is comprehensively judged whether the speed control system adopts the power mode AGC control process S2 or the power mode primary frequency regulation control process S3 to complete the power regulation task and realize the switching of various regulation modes of primary frequency regulation and secondary frequency regulation to meet the needs of power frequency regulation of the hydro-turbine generator set under different working conditions.

[0035] A further solution is a control mode comprehensive selection process S1, the steps of which are as follows:

[0036] Condition 1: Calculate whether the grid frequency Fgrid exceeds the primary frequency regulation dead band Fdeadband. The formula is as follows:

[0037] |Fgrid-50|>Fdeadband; where Fgrid represents the grid frequency, and Fdeadband represents the primary frequency regulation dead zone;

[0038] Condition 2: Calculate whether the AGC given value Pset of the unit issued by the computer monitoring system received by the speed governor is updated. The calculation formula is as follows:

[0039] |Pset-Pset_pre|≥P_pa;

[0040] Where: Pset represents the AGC given value of the unit issued by the computer monitoring system;

[0041] Pset_pre indicates the AGC given value of the unit issued by the computer monitoring system in the previous cycle;

[0042] P_pa indicates the threshold for judging whether the power given value has changed. It can be set manually. Its default parameter is slightly smaller than the minimum step size of the AGC change.

[0043] If condition 1 is met, the power mode is entered into the frequency modulation mode, and then the S3 unit is entered;

[0044] If condition 1 is not met, and condition 2 is met, then enter unit S2;

[0045] If both conditions 1 and 2 are met, enter unit S3.

[0046] A further solution is the power mode AGC control process S2:

[0047] 1) After entering the governor power mode AGC control process S2, the governor uses the power ACG regulation model independent of the primary frequency regulation to complete power regulation according to the power control target value Pset of the hydro-turbine generator set issued by the monitoring system, until the power of the regulated unit enters the power regulation dead zone, that is, |Pset-Pg|≤Pdeadband, and the process ends;

[0048] Where: Pset: AGC set value issued by the computer monitoring system; Pg: actual power of the unit; Pdeadband: dead band of power regulation of the unit;

[0049] 2) During the adjustment process of the power AGC adjustment model, a frequency adjustment action is performed, and the frequency adjustment model S3 unit is automatically entered at this time, until the frequency adjustment is completed and the power adjustment is completed, then the process ends.

[0050] Judgment of the end of primary frequency regulation: |Fgrid-50|≤Fdeadband; where Fgrid represents the grid frequency, and Fdeadband represents the primary frequency regulation dead zone;

[0051] Power regulation technical judgment: |Pset-Pg|≤Pdeadband, Pset: the AGC given value of the unit issued by the computer monitoring system; Pg: the actual power generated by the unit; Pdeadband: the dead zone of power regulation of the unit.

[0052] A further solution is that the power mode primary control process S3:

[0053] When the grid frequency does not receive the new AGC adjustment command issued by the hydropower station computer monitoring system, the power mode primary frequency regulation control process S3 is adopted by default, that is, the difference between the current computer monitoring system active setting value Pset and the previous cycle computer monitoring system active setting value Pset_pre is calculated to see whether it is greater than the preset value P_pa, |Pset-Pset_pre|≥P_pa, and automatically enters S2.

[0054] A further solution is to determine whether the primary frequency modulation is an action unit S4 during the AGC process:

[0055] During the AGC adjustment process of the hydropower generator power mode, it is calculated whether the grid frequency exceeds the dead zone of the primary frequency regulation. When the frequency exceeds the dead zone, it automatically enters the S3 unit and the process ends; otherwise, continue to use the S2 unit to carry out power regulation.

[0056] Example 2

[0057] like Figures 1 to 6As shown, as a further optimization of Example 1, based on Example 1, this embodiment also includes the following technical features:

[0058] The purpose of the present invention is to ensure the stability of the primary frequency regulation under the asynchronous networking operation mode, while improving the AGC regulation speed when the primary frequency regulation is not in operation, thereby improving the power frequency regulation capability of the hydro-generator set on the power supply side and improving the power-frequency support capability of the power grid.

[0059] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0060] A method for coordinated control of primary frequency regulation and AGC under power mode of a hydro-turbine generator set is disclosed, wherein the units adopted include a control mode comprehensive selection process S1 unit, a power mode AGC control process S2 unit, a power mode primary frequency regulation control process S3 unit, and an AGC regulation process primary frequency regulation judgment process S4 unit; wherein when the power mode AGC control process S2 unit or the power mode primary frequency regulation control process S3 unit is selected through the S1 unit, power regulation under different working conditions is realized through different regulation models of the S2 and S3 units, thereby improving the support capability.

[0061] The further solution is the control method selection process:

[0062] In the default mode, the power closed loop is adjusted according to the last adjustment model. That is, if there is no new condition trigger, the current power closed loop adjustment will be carried out according to the last adjustment model.

[0063] When the grid frequency exceeds the primary frequency regulation dead zone, regardless of whether a new AGC command is issued, the S3 unit is automatically selected for power closed-loop regulation;

[0064] When the grid frequency does not exceed the power dead zone, if there is a new AGC adjustment instruction from the computer monitoring system, the S2 unit will be automatically selected for power closed-loop adjustment.

[0065] A further solution is that the power mode primary frequency modulation control process unit:

[0066] The speed governor completes the power regulation according to the power control target value Pset of the turbine generator set issued by the monitoring system, using the power ACG regulation model that is independent of the primary frequency regulation, until the power of the regulated unit enters the power regulation dead zone, that is, |Pset-Pg|≤Pdeadband, and the process ends; where: Pset: the AGC given value of the unit issued by the computer monitoring system; Pg: the actual power of the unit; Pdeadband: the power regulation dead zone of the unit.

[0067] A further solution is that the power mode primary frequency modulation control process unit:

[0068] When the primary frequency regulation is in action (|Fgrid-50|>Fdeadband), the power regulation and primary frequency regulation are realized by adopting the secondary frequency regulation model in power mode according to the power control target value Pset and frequency difference Fgrid-50 of the turbine generator set issued by the monitoring system; when the primary frequency regulation is restored (|Fgrid-50|≤Fdeadband) and the unit power enters the power regulation dead zone, that is, |Pset-Pg|≤Pdeadband, the process ends.

[0069] A further solution is that the frequency modulation judgment process S4 unit in the AGC adjustment process:

[0070] During the adjustment process of the power mode primary frequency modulation control process S2 unit, when the primary frequency modulation is in action (|Fgrid-50|>Fdeadband), the power mode primary frequency modulation control process S3 unit is automatically switched; otherwise, the power mode primary frequency modulation control process S2 unit is maintained in the adjustment process.

[0071] As described above, the present invention can be preferably implemented.

[0072] All features disclosed in all embodiments in this specification, or steps in all methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined and / or expanded or replaced in any manner.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. According to the technical essence of the present invention, within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed regulator, characterized in that: The operating status of the hydropower unit is judged by combining the grid frequency, the primary frequency regulation status of the speed regulation system and the AGC control instructions, and different adjustment methods are selected to perform power closed-loop regulation on the speed regulator.

2. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 1, characterized in that: The method includes the steps of comprehensive selection of control modes: selecting a power mode AGC control mode or a power mode primary frequency modulation control mode for power closed-loop regulation.

3. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 2, characterized in that: The basis for comprehensive selection of control methods includes: A. When the grid frequency exceeds the primary frequency regulation dead zone, regardless of whether there is a new AGC regulation command issued by the wheel, the power mode primary frequency regulation control method is automatically selected for power closed-loop regulation.

4. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 3, characterized in that: The basis for comprehensive selection of control methods includes: B. When the grid frequency does not exceed the power dead zone, if there is a new AGC adjustment instruction from the computer monitoring system, the power mode AGC control method will be automatically selected for power closed-loop regulation.

5. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 2, characterized in that: The basis for comprehensive selection of control methods includes: C. Except for situations A and B, the previous regulation cycle regulation control mode is maintained for power closed-loop regulation.

6. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 3, characterized in that: When the power mode AGC control method is used for power closed-loop regulation, the speed governor uses the power mode AGC control method to complete power regulation according to the hydropower unit power control target value Pset issued by the monitoring system, until the regulated unit power enters the power regulation dead zone, and the power closed-loop regulation ends; the formula for the unit power entering the power regulation dead zone is: |Pset-Pg|≤Pdeadband; where Pset represents the unit AGC given value issued by the computer monitoring system, Pg represents the unit actual power, and Pdeadband represents the unit power regulation dead zone.

7. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 4, characterized in that: During the adjustment process using the power mode AGC control method, if the primary frequency modulation is activated, the power mode primary frequency modulation control method will be automatically entered until the primary frequency modulation adjustment is completed and the power adjustment is completed.

8. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 5, characterized in that: The judgment formula for the end of primary frequency regulation is: |Fgrid-50|≤Fdeadband; where Fgrid represents the grid frequency, and Fdeadband represents the primary frequency regulation dead zone.

9. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 5, characterized in that: The power regulation completion judgment formula is: |Pset-Pg|≤Pdeadband; where Pset represents the AGC given value of the unit issued by the computer monitoring system, Pg represents the actual power generated by the unit, and Pdeadband represents the power regulation dead zone of the unit.

10. A method for coordinated control of primary frequency regulation and AGC of a hydropower unit speed governor according to claim 2, characterized in that: When the grid frequency does not receive the new AGC adjustment command issued by the hydropower station computer monitoring system, the power mode primary frequency regulation control method is adopted by default; if |Pset-Pset_pre|≥P_pa, the power mode AGC control method is automatically entered; where Pset represents the calculation of the current active setting value of the computer monitoring system, and P_pa represents the preset value P_pa.

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