A method for increasing the frequency modulation response speed of a unit by using heat supply steam

Abstract

This invention discloses a method for increasing the frequency regulation response speed of a generating unit using heating steam. The method includes comparing the difference between the unit load command and the actual load deviation; and executing valve closing or opening actions based on the range of the obtained difference: when the unit load command is greater than the actual load deviation and the difference is greater than a preset peak value, the valve is closed, and the valve closing range is determined according to the load range to reduce the amount of steam extracted from the unit; when the unit load command is greater than the actual load deviation and the difference is less than a preset valley value, the valve is opened, and the valve opening range is determined according to the load range, with the maximum opening range being the original valve opening, increasing the amount of steam extracted from the unit. This method allows for valve opening adjustment based on the comparison between the unit load command and the actual load deviation, thereby improving the unit's frequency regulation response speed.

Description

Technical Field

[0001] This invention belongs to the field of frequency regulation of cogeneration units, and specifically relates to a method for increasing the frequency regulation response speed of the unit by using heating steam. Background Technology

[0002] With the vigorous development of new energy sources and the energy crisis, the quality of coal used in thermal power plants is far lower than the design coal type, resulting in poor system adjustability, slow frequency regulation response of units, inability to meet the requirements of the existing power grid, and facing power grid assessment.

[0003] Therefore, to address the issue of slow frequency regulation response speed of the unit, this solution proposes a method to increase the frequency regulation response speed of the unit by using heating steam. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a method for increasing the frequency regulation response speed of a unit by using heating steam. The method can adjust the valve opening according to the comparison between the unit load command and the actual unit load, thereby improving the frequency regulation response speed of the unit.

[0005] Technical solution: To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for increasing the frequency regulation response speed of a generating unit using heating steam includes the following steps:

[0007] The unit load command is compared with the actual unit load, and the difference between the unit load command and the actual unit load is calculated in real time. This difference is equal to the unit load command minus the actual unit load.

[0008] Based on the range of the obtained difference, the valve is either closed or opened.

[0009] When the unit load command is greater than the actual unit load and the difference is greater than the preset peak value, the valve will be closed. The valve closure range will be determined according to the load range to reduce the amount of steam extracted from the unit.

[0010] When the unit load command is greater than the actual unit load, and the difference is less than the preset valley value, the valve is opened. The valve opening range is determined according to the load range, and the maximum opening range is the original valve opening, which increases the amount of steam extracted from the unit.

[0011] Furthermore, let the actual load rate be F%, and the valve closing adjustment range be S. 关 Then we have:

[0012] S 关 =293.4 - 12.53*F + 0.1850*F 2 - 0.000920*F3 .

[0013] Furthermore, the valve closure has a lower limit for valve opening, and the extraction steam passage is in a conducting state when the valve is at its lower opening limit.

[0014] Furthermore, the valve opening is limited to 15%.

[0015] Furthermore, let the actual load rate be F%, and the valve opening rate be S. 开 Then we have:

[0016] S 开 = 21.72 - 0.9588*F + 0.01465*F 2 - 0.000075*F 3 .

[0017] Furthermore, during the valve opening process, the valve opens to its original opening degree at a rate greater than the rate at which the valve closes.

[0018] Furthermore, based on the pressure range of the extraction steam channel, it is determined whether the unit is in operation. When the unit is in operation, the lower limit of valve opening is set to 15%, and when it is not in operation, the lower limit of valve opening is 0%.

[0019] Furthermore, the valve is located at the lower exhaust pipe of the low-pressure cylinder of the unit, and the steam goes directly to the heating network system through the valve.

[0020] Beneficial effects: This invention can adjust the valve opening based on the comparison between the unit load command and the actual unit load, thereby improving the unit's frequency regulation response speed. Attached Figure Description

[0021] Appendix Figure 1 This is a flowchart illustrating the overall process of the present invention.

[0022] Appendix Figure 2 This is a schematic diagram showing the position of the valve of the present invention in a pipeline. Detailed Implementation

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] As attached Figure 1 and attached Figure 2 As shown, a method for increasing the frequency regulation response speed of a generator unit using heating steam includes the following steps:

[0025] The unit load command is compared with the actual unit load, and the difference between the unit load command and the actual unit load is calculated in real time. This difference is equal to the unit load command minus the actual unit load.

[0026] Based on the range of the obtained difference, the valve is either closed or opened.

[0027] When the unit load command is greater than the actual unit load and the difference is greater than the preset peak value, the valve will be closed. The valve closure range will be determined according to the load range to reduce the amount of steam extracted from the unit.

[0028] When the unit load command is greater than the actual unit load, and the difference is less than the preset valley value, the valve is opened. The valve opening range is determined according to the load range, and the maximum opening range is the original valve opening, which increases the amount of steam extracted from the unit.

[0029] During the heating season, the steam extraction flow rate can be adjusted to quickly respond to grid frequency regulation. By flexibly changing the extraction steam volume, the grid frequency regulation response speed can be met, reducing the frequency regulation assessment of cogeneration units during the heating season.

[0030] The extent to which a valve is closed directly affects the amount of steam extracted from the unit. If the amount of steam extracted decreases, the amount of steam entering the unit will increase significantly, thereby increasing the unit's work capacity. This combined effect will directly impact the frequency regulation response speed.

[0031] Let the actual load rate be F%, and the valve closing adjustment range be S. 关 Then we have:

[0032] S 关 =293.4 - 12.53*F + 0.1850*F 2 - 0.000920*F 3 .

[0033] Specifically, the valve closing adjustment range is shown in Table 1, depending on the load rate:

[0034]

[0035] During the valve closing process:

[0036] Permissible conditions: Unit shut down at zero output; intermediate discharge pressure < 0.5 MPa.

[0037] Operating conditions: The difference between the unit load command and the actual unit load is greater than 6MW.

[0038] Specific requirements:

[0039] When the load is above 80%, the valve will automatically close by 5% (duration 60 seconds, the same applies below).

[0040] When the load is 70-80%, the valve automatically closes by 7.5%; when the load is 60-70%, the valve automatically closes by 10%.

[0041] When the load is 50-60%, the valve automatically closes by 15%; when the load is 45-50%, the valve automatically closes by 20%.

[0042] When the load is 40-45%, the valve will automatically close by 30%.

[0043] The valve is closed with a lower limit to its opening degree, and the extraction steam passage is open when the valve is at its lower opening limit. The valve opening degree is limited to 15%.

[0044] Let the actual load rate be F%, and the valve opening rate be S. 开 Then we have:

[0045] S 开 = 21.72 - 0.9588*F + 0.01465*F 2 - 0.000075*F 3 .

[0046] Specifically, the valve opening rate varies depending on the load rate, as shown in Table 2:

[0047]

[0048] During the valve opening process:

[0049] Operating conditions: The difference between the unit load command and the actual unit load is less than 3MW, and the operating process lasts for 10 seconds.

[0050] Valves operating at 80% or higher loads are opened to their original opening degree at a rate of 0.5% / s.

[0051] When the load is 70-80%, the valve opens to its original opening degree at a rate of 0.75% / s.

[0052] When the load is 60-70%, the valve opens to its original opening degree at a rate of 0.8% / s.

[0053] When the load is 50-60%, the valve opens to its original opening degree at a rate of 1% / s.

[0054] When the load is 45-50%, the valve opens to its original opening degree at a rate of 1.5% / s.

[0055] When the load is 40-45%, the valve opens to its original opening degree at a rate of 2% / s.

[0056] During the valve opening process, the rate at which the valve opens to its original opening degree is greater than the rate at which the valve closes. The opening and closing speed directly affects the instantaneous amount of steam extracted, resulting in the rate of change in the amount of steam entering the unit, thus affecting the unit's work rate and the regulation rate.

[0057] Based on the pressure range of the extraction steam channel, determine whether the unit is in operation. When the unit is in operation, the lower limit of valve opening is set to 15%, and when it is not in operation, the lower limit of valve opening is 0%.

[0058] As attached Figure 2 As shown, the valve is located at the lower exhaust pipe of the low-pressure cylinder of the unit. Steam goes directly to the heating network system through the valve. In this scheme, two sets of valves 1 are connected in parallel in the pipeline system. By superimposing the actions of multiple valves, the adjustment can be carried out quickly, thereby improving the unit's response rate.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for increasing the frequency modulation response speed of a unit by using heat supply steam, characterized in that, Includes the following steps: Compare the unit load command with the actual unit load, and calculate the difference between the unit load command and the actual unit load in real time. This difference = unit load command - actual unit load. Based on the range of the obtained difference, the valve is either closed or opened. When the unit load command is greater than the actual unit load and the difference is greater than the preset peak value, the valve will be closed. The valve closure range will be determined according to the load range to reduce the amount of steam extracted from the unit. When the unit load command is greater than the actual unit load and the difference is less than the preset valley value, the valve is opened. The valve opening range is determined according to the load range, and the maximum opening range is the original valve opening, which increases the amount of steam extracted from the unit.

2. The method of claim 1, wherein the method further comprises: Let the load rate of the actual load be F%, and the closing adjustment range of the valve be S 关 Then, S 关 = 293.4 - 12.53*F + 0.1850*F 2 - 0.000920*F 3 .

3. The method of claim 2, wherein the method further comprises: When the valve is closed, there is a lower limit to the valve opening, and when the valve is at the lower limit of the valve opening, the extraction steam passage is in a conductive state.

4. The method of claim 3, wherein the method further comprises: The valve opening is limited to 15%.

5. The method for increasing the frequency regulation response speed of a generator unit using heating steam according to claim 1, characterized in that: Let the load rate of the actual load be F%, and the opening rate of the valve be S 开 Then, there is: S 开 = 21.72 - 0.9588*F+ 0.01465*F 2 - 0.000075*F 3 .

6. The method for increasing the frequency modulation response speed of a unit by using heat supply steam according to claim 5, characterized in that: During the valve opening process, the valve opens to its original opening degree at a rate greater than the valve closing rate.

7. The method of claim 1, wherein the method further comprises: Based on the pressure range of the extraction steam channel, determine whether the unit is in operation. When the unit is in operation, the lower limit of valve opening is set to 15%, and when it is not in operation, the lower limit of valve opening is 0%.

8. The method of claim 1, wherein the method further comprises: The valve is located at the lower exhaust pipe of the low-pressure cylinder of the unit, and the steam goes directly to the heating network system through the valve.

Images