Method for increasing the pump operating range of a variable speed pumped storage unit

Abstract

The application provides a method for increasing the regulating range of pump working condition of variable-speed pumped storage unit, finds the coordinated working condition point in the hump area through the safety margin point of pump working condition and coordinated working condition opening, and replaces the opening coordinated working condition point in the hump area with the optimal efficiency point not in the hump area under the equal input condition, and then obtains the optimized operation curve of the pump working condition of pumped storage unit. The pump working condition of variable-speed pumped storage unit is operated according to the optimized operation curve under variable speed, the influence of the hump area can be avoided, and the regulating range under the pump working condition is greatly increased.

Description

Technical Field

[0001] This invention belongs to the technical field of pumped storage unit control methods, specifically relating to a method for increasing the input adjustment range of pumps in variable speed pumped storage units. Background Technology

[0002] Variable-speed pumped storage units (PSGs) offer advantages such as fast power response, adjustable pump input, and high hydraulic efficiency. They exhibit excellent regulation performance on both long and short timescales, effectively addressing the instability issues brought about by the large-scale grid connection of new energy sources to the new power system. While operating the pumps of PSGs according to the cooperative opening curve at varying speeds ensures optimal hydraulic efficiency, the low-load operating point of the cooperative opening curve lies within the hump region, affecting the safe and stable operation of the unit. Currently, to eliminate the impact of the hump region on unit stability, a common method is to set a "hump limit line" on the cooperative opening curve (composed of head safety margin points at different speeds). PSGs can only operate below this limit line. While this method ensures unit stability, it significantly reduces the pump input adjustment range (generally only reaching 60-100% of rated power), severely impacting the unit's regulation capability during periods of low power system load. Summary of the Invention

[0003] The purpose of this invention is to provide a method for increasing the input adjustment range of pumps in variable speed pumped storage units. This method can greatly improve the input adjustment range under pump operating conditions while effectively avoiding the impact of the hump zone on the stability of the unit.

[0004] The technical solution adopted in this invention is: a method for increasing the adjustment range of the pump input under the operating conditions of a variable speed pumped storage unit, and the specific operation steps are as follows:

[0005] Step 1: Collect data on the pump operation conditions and coordination points of the pumped storage unit, including the pump opening degree. α ,flow Q Yangcheng H , input force P Data, as well as basic performance data of the pump under different opening conditions, including opening-flow-head data and opening-flow-in force data;

[0006] Step 2, based on the opening degree of the coordinated working point. α i i=1……n, where n represents the number of cooperative opening conditions and the basic performance data of the pump at different opening degrees, and the opening degree is calculated. α i The head corresponding to the safety margin of the lower head H soi ;

[0007] Step 3: Determine the head at the opening coordination point. H i Is it less than H soi ,like H i Less than H soi This indicates that the operating point is not within the hump zone; proceed to step 9. H i Not less than H soi This indicates that the operating point is within the hump zone; proceed to step 4.

[0008] Step 4, based on the input force at the coordinated working point P i Based on the basic performance data of the pump under different opening degrees, the input force at different opening degrees was calculated. P i The data corresponding to the operating points, including the opening degree α j j=1……m, where m represents the number of equal input working points and flow rate under different opening degrees. Q j Yangcheng H j data;

[0009] Step 5, according to α j Basic performance data for different pump opening degrees under different operating conditions, calculation α j The head corresponding to the safety margin of the lower head H soj ;

[0010] Step 6, Determine H j Is it less than H soj ,like H j Less than H soj If this indicates that the operating point is not within the hump zone, then retain the data for that operating point and proceed to step 7; if H j Not less than H soj If this indicates that the operating point is within the hump zone, then delete the data for that operating point and proceed to step 7.

[0011] Step 7, obtain the input force under different opening degrees. P i Furthermore, identify the operating points not located within the hump zone, and pinpoint the data corresponding to the operating point with the highest flow rate, including the opening degree. αi_new ,flow Q i_new Yangcheng H i_new ;

[0012] Step 8, use the opening obtained in step 7. α i_new ,flow Q i_new Yangcheng H i_new The data of the opening degree coordination working point located in the hump area is updated to obtain improved opening degree coordination working point data;

[0013] Step 9: Obtain the optimized operating curve data of the pump operating conditions based on Step 3 and Step 8, including the original cooperative opening condition point data outside the hump region and the updated cooperative opening condition point data within the hump region.

[0014] The invention is further characterized by:

[0015] Step 2 Calculation H soi The calculation formula is:

[0016] (1);

[0017] In equation (1), α osm Represents operational safety margin. H maxpsi Represents openness α i The head corresponding to the lowest point of the lower hump characteristic.

[0018] By using the optimal efficiency operating point that is not in the hump zone under the same power, the opening coordination operating point located in the hump zone is replaced, thereby ensuring the stable operation of the pump in the low-load zone of the variable speed pumped storage unit.

[0019] In step 5 H soj The calculation formula is:

[0020] (2);

[0021] In equation (2), H maxpsj Represents openness α j The head corresponding to the lowest point of the lower hump characteristic.

[0022] The safety margin in steps 2 and 5 is defined as the head difference between the highest head margin point and the lowest point of the hump characteristic. H osm With maximum operating head Hmaxps The ratio of can be calculated using the following formula:

[0023] (3)

[0024] The basis for determining that the operating point with the maximum flow rate in step 7 is the same as the operating point with the optimal efficiency is: under the same input conditions, the flow rate and efficiency of the pump in a pumped storage unit are directly proportional. The formula for calculating the pump efficiency is:

[0025] (4);

[0026] In equation (4), η Represents efficiency. ρ Represents the density of water. g It represents gravitational acceleration.

[0027] The beneficial effects of this invention are as follows: The method for increasing the input adjustment range of the pump in a variable-speed pumped storage unit utilizes the optimal efficiency operating point outside the peak area (or peak area) under the same power rating to replace the opening coordination operating point located in the peak area. This significantly increases the adjustment range of the pump while ensuring stable unit operation. By replacing the opening coordination operating point located in the peak area with the optimal efficiency operating point outside the peak area under the same power rating, an optimized operating curve for the pump can be obtained. When the pump of the variable-speed pumped storage unit operates according to the optimized operating curve, it not only avoids the influence of the peak area but also greatly increases the input adjustment range of the pump. Attached Figure Description

[0028] Figure 1 This is a flowchart of the method for increasing the input force adjustment range of the pump in the variable speed pumped storage unit according to the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the operational safety margin of the method for increasing the input adjustment range of the pump in operation of the variable speed pumped storage unit according to the present invention.

[0030] Figure 3 This invention relates to the method for increasing the input adjustment range of the pump in the variable speed pumped storage unit, and the opening-flow curve of the cooperative opening condition.

[0031] Figure 4 This invention provides the flow-head curve of the method for increasing the input adjustment range of the pump in the variable speed pumped storage unit under the cooperating opening condition.

[0032] Figure 5 This invention provides the flow-in force curve for the coordinated opening condition of the method for increasing the pump input adjustment range of variable speed pumped storage units.

[0033] Figure 6This invention relates to the method for increasing the input adjustment range of pumps in variable speed pumped storage units, specifically the pump operating condition basic performance curve, which is the opening-flow-head curve.

[0034] Figure 7 This invention relates to the method for increasing the input range of pumps in variable speed pumped storage units, specifically the pump operating condition basic performance curve, which is the opening-flow-input curve.

[0035] Figure 8 This invention relates to the relationship between the cooperative opening point and the hump region when the opening of the pump in the variable speed pumped storage unit is 26°, which is the method for increasing the pump input adjustment range of the variable speed pumped storage unit.

[0036] Figure 9 This invention relates to the relationship between the cooperative opening point and the hump region when the opening degree is 12° in the method for increasing the pump input adjustment range of variable speed pumped storage units.

[0037] Figure 10 This invention provides the method for increasing the pump input range of variable speed pumped storage units, showing the opening-flow-head curves at different opening degrees for an input of 239.39 MW.

[0038] Figure 11 This is the flow-head characteristic curve of the optimized operating curve of the method for increasing the pump input adjustment range of variable speed pumped storage unit according to the present invention.

[0039] Figure 12 This is the flow-input characteristic curve of the optimized operating curve of the method for increasing the pump input adjustment range of variable speed pumped storage unit according to the present invention;

[0040] Figure 13 This invention increases the adjustment range of the pump operating conditions of the variable speed pumped storage unit before the invention.

[0041] Figure 14 This invention relates to the method for increasing the input range of the pump operating conditions of a variable speed pumped storage unit. After using this invention, the adjustment range of the pump operating conditions of the variable speed pumped storage unit is increased. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, so that the advantages and features of the present invention can be more readily understood by those skilled in the art.

[0043] The present invention provides a method for increasing the input adjustment range of the pump in a variable-speed pumped storage unit, such as... Figure 1 As shown, the specific operation steps are as follows:

[0044] Step 1: Collect data on the pump operation conditions and coordination points of the pumped storage unit, including the pump opening degree. α ,flowQ Yangcheng H , input force P Data, as well as basic performance data of the pump under different opening conditions, including opening-flow-head data and opening-flow-in force data;

[0045] Step 2, based on the opening degree of the coordinated working point. α i (i=1……n, where n represents the number of cooperative opening conditions) and basic performance data of the pump at different opening degrees, calculate the opening degree. α i The head corresponding to the safety margin of the lower head H soi ;

[0046] Step 3, Determine H i Is it less than H soi .like H i Less than H soi This indicates that the operating point is not within the hump zone; proceed to step 9. H i Not less than H soi This indicates that the operating point is within the hump zone; proceed to step 4.

[0047] Step 4, based on the input force at the coordinated working point P i Based on the basic performance data of the pump under different opening degrees, the input force at different opening degrees was calculated. P i The data corresponding to the operating points, including the opening degree α j (j=1……m, where m represents the number of equal input operating points under different opening degrees), flow rate Q j Yangcheng H j data;

[0048] Step 5, according to α j Basic performance data for different pump opening degrees under different operating conditions, calculation α j The head corresponding to the safety margin of the lower head H soj ;

[0049] Step 6, Determine H j Is it less than H soj .like H jLess than H soj If this indicates that the operating point is not within the hump zone, then retain the data for that operating point and proceed to step 7; if H j Not less than H soj If this indicates that the operating point is within the hump zone, then delete the data for that operating point and proceed to step 7.

[0050] Step 7, obtain the input force under different opening degrees. P i Furthermore, identify the operating points not located within the hump zone, and pinpoint the data corresponding to the operating point with the highest flow rate (i.e., the highest efficiency point), including the opening degree. α i_new ,flow Q i_new Yangcheng H i_new ;

[0051] Step 8: Use the opening degree, flow rate, and head data obtained in Step 7 to update the opening degree coordination condition point data located in the hump area to obtain improved opening degree coordination condition point data.

[0052] Step 9: Based on Step 3 and Step 8, obtain the optimized operating curve data of the pump, including the original cooperative opening condition point data outside the hump region and the updated cooperative opening condition point data within the hump region.

[0053] Step 2 Calculation H soi The calculation formula is:

[0054] (1);

[0055] In equation (1), α osm Represents operational safety margin. H maxpsi Represents openness α i The head corresponding to the lowest point of the lower hump characteristic.

[0056] By using the optimal efficiency operating point that is not in the hump zone under the same power, the opening coordination operating point located in the hump zone is replaced, thereby ensuring the stable operation of the pump in the low-load zone of the variable speed pumped storage unit.

[0057] In step 5 H soj The calculation formula is:

[0058] (2);

[0059] In equation (2), Hmaxpsj Represents openness α j The head corresponding to the lowest point of the lower hump characteristic.

[0060] The safety margin in steps 2 and 5 is defined as the head difference between the highest head margin point and the lowest point of the hump characteristic. H osm With maximum operating head H maxps The ratio of can be calculated using the following formula:

[0061] (3);

[0062] The corresponding diagram is as follows Figure 2 As shown.

[0063] The basis for determining that the operating point with the maximum flow rate in step 7 is the same as the operating point with the optimal efficiency is: under the same input conditions, the flow rate and efficiency of the pump in a pumped storage unit are directly proportional. The formula for calculating the pump efficiency is:

[0064] (4);

[0065] In equation (4), η Represents efficiency. ρ Represents the density of water. g It represents gravitational acceleration.

[0066] By replacing the optimal efficiency operating point outside the hump region with the opening coordination operating point located in the hump region under the same power, optimized operating curve data for pump operation can be obtained. Operating the pump of the variable-speed pumped storage unit according to the optimized operating curve not only avoids the influence of the hump region but also greatly increases the input adjustment range under pump operation conditions.

[0067] Example

[0068] Taking a pumped storage unit in actual operation as an example, the safety margin α osm Taking 2%, the present invention will be discussed in detail.

[0069] Step 1: Collect data on the pump operation and coordination opening points of the pumped storage unit, including... α-Q Curve (e.g.) Figure 3 (as shown) Q - H Curve (e.g.) Figure 4 (as shown) Q - P Curve (e.g.) Figure 5 As shown), and basic performance data of the pump at different opening degrees, including α - Q - HCurve (e.g.) Figure 6 (as shown) α - Q - P Data curves (such as) Figure 7 (as shown)

[0070] Step 2, based on the opening degree of the coordinated working point. α i (i=1……n, where n represents the number of cooperative opening conditions) and basic performance data of the pump under different opening conditions, calculate the opening. α i The head corresponding to the safety margin of the lower head H soi ; H soi The calculation formula is:

[0071] (1);

[0072] In equation (1), α osm Represents operational safety margin. H maxpsi Represents openness α i The head corresponding to the lowest point of the lower hump characteristic.

[0073] Step 3, Determine H i Is it less than H soi .like H i Less than H soi This indicates that the operating point is not within the hump zone. Proceed to step 9, such as the opening degree. α i At 26°, the corresponding coordinated head H i The head is 395.32 m, and the head corresponding to the head safety margin at this opening is... H soi It is 455.29 m, at this time H i < H soi This indicates the degree of openness. α i The coordinating opening condition at 26° is not within the hump region (e.g.) Figure 8 (As shown), then no action is required; if H i Not less than H soi This indicates that the operating point is within the hump zone, such as the opening degree. α iWhen the angle is 12°, the corresponding coordinated head is H i The head is 497.67 m, and the head corresponding to the head safety margin at this opening is... H soi It is 487.93m, at this time H i > H soi This indicates the degree of openness. α i The coordinating opening condition at 12° is within the hump region (e.g.) Figure 9 As shown), the coordinating operating point needs to be corrected and updated (at this time, the input force...). P i (239.39MW)

[0074] Step 4, based on the input force at the coordinated working point P i Based on the basic performance data of the pump under different opening degrees, the input force at different opening degrees was calculated. P i The data corresponding to the working point, with input force P i Taking 239.39 MW as an example, the corresponding image is as follows: Figure 10 As shown;

[0075] Step 5, according to α j Basic performance data for different pump opening degrees under different operating conditions, calculation α j The head corresponding to the safety margin of the lower head H soj ; H soj The calculation formula is:

[0076] (2);

[0077] In equation (1), H maxpsj Represents openness α j The head corresponding to the lowest point of the lower hump characteristic.

[0078] Step 6, Determine H j Is it less than H soj .like H j Less than H soj This indicates that the operating point is not within the hump zone, so the data for that operating point should be retained. (For example, input force...) P i239.39 MW, opening degree α j When the angle is 10°, the corresponding head is H j The head is 490.51 m, and the head corresponding to the head safety margin at this opening is... H soj It is 499.43 m, at this time H i < H soi This indicates the degree of openness. α i If the operating point at 10° is not within the hump region, then the data for that operating point is retained; if... H j Not less than H soj If this indicates that the operating point is within the hump zone, then the data for that operating point should be deleted. (For example, input force...) P i 239.39 MW, opening degree α j At a radius of 16°, the corresponding head H j The head is 492.44 m, and the head corresponding to the head safety margin at this opening is... H soj It is 481.85 m, at this time H i > H soi This indicates the degree of openness. α i If the operating point at 16° is not within the hump region, then delete the data for that operating point.

[0079] Step 7, obtain the input force under different opening degrees. P i Furthermore, for operating points not located within the hump zone, identify the operating point with the highest flow rate (i.e., the point of highest efficiency) and use the opening degree... P i Taking 239.39 MW as an example, the data for the operating point with the maximum flow rate are: opening degree 10.8° and flow rate 42.93 m³ / h. 3 / s, head 494.68 m;

[0080] Including opening α i_new ,flow Q i_new Yangcheng H i_new ;

[0081] Step 8: Update the data of the opening degree coordination point located in the hump area with the opening degree, flow rate, and head data obtained in Step 7, using the opening degree...P i Taking 239.39 MW as an example, the original coordinated operating point data consisted of an opening of 12° and a flow rate of 43.32 m³ / s. 3 / s, head 497.67 m updated to opening 10.8°, flow rate 42.93 m³ / s 3 / s, head 494.68 m;

[0082] Step 9: Based on Steps 3 and 8, obtain the optimized operating curve data for the pump, including the original cooperative opening point data outside the hump region and the updated cooperative opening point data within the hump region, thus optimizing the operating curve. Q - H Curves Figure 11 As shown, the optimized running curve Q - P Curves Figure 12 As shown.

[0083] This invention replaces the opening coordination operating point located in the hump region with the efficiency-optimal operating point that is not in the hump region under the same power. Therefore, this method can not only prevent the pump operating condition of the variable speed pumped storage unit from operating in the hump region, but also greatly increase the adjustment range of the unit's pump operating condition.

[0084] Taking a real pumped storage power station as an example, the adjustment range of the pump operating conditions of the variable speed pumped storage unit before using this invention is as follows: Figure 13 As shown, the adjustment range of the pump operating conditions of the variable speed pumped storage unit after using the present invention is as follows: Figure 14 As shown. Before using this invention, the unit could only operate in region A, while region B was a hump-restricted region. After using this invention, it can operate not only in region A but also in region B. Theoretically, the unit's input adjustment range is increased from 74-100% to over 35-100%.

Claims

1. A method for increasing the input adjustment range of a variable-speed pumped storage unit pump under operating conditions, characterized in that, The specific steps are as follows: Step 1: Collect data on the pump operation conditions and coordination points of the pumped storage unit, including the pump opening degree. α ,flow Q Yangcheng H , input force P Data, as well as basic performance data of the pump under different opening conditions, including opening-flow-head data and opening-flow-in force data; Step 2, based on the opening degree of the i-th cooperating working point α i Basic performance data for pump operating conditions at different opening degrees, and calculation of opening degree. α i The head corresponding to the safety margin of the lower head H soi Where i=1……n, and n represents the number of cooperative opening condition points; Step 2 Calculation H soi The calculation formula is: （1）； In equation (1), α osm Represents operational safety margin. H maxpsi Represents openness α i The head corresponding to the lowest point of the lower hump characteristic; Step 3: Determine the head at the i-th opening coordination point. H i Is it less than H soi ,like H i Less than H soi This indicates that the operating point is not within the hump zone; proceed to step 9. H i Not less than H soi This indicates that the operating point is within the hump zone; proceed to step 4. Step 4, based on the input force at the i-th coordinating working point P i Based on the basic performance data of the pump under different opening degrees, the input force at different opening degrees was calculated. P i The data corresponding to the operating points, including the opening degree α j Where j=1……m, m represents the number of equal input working points and the flow rate under different opening degrees. Q j Yangcheng H j data; Step 5, according to α j Basic performance data for different pump opening degrees under different operating conditions, calculation α j The head corresponding to the safety margin of the lower head H soj ; In step 5 H soj The calculation formula is: （2）； In equation (2), H maxpsj Represents openness α j The head corresponding to the lowest point of the lower hump characteristic; Step 6, Determine H j Is it less than H soj ,like H j Less than H soj If this indicates that the operating point is not within the hump zone, then retain the data for that operating point and proceed to step 7; if H j Not less than H soj If this indicates that the operating point is within the hump zone, then delete the data for that operating point and proceed to step 7. Step 7, obtain the input force under different opening degrees. P i Furthermore, identify the operating points not located within the hump zone, and pinpoint the data corresponding to the operating point with the highest flow rate, including the opening degree. α i_new ,flow Q i_new Yangcheng H i_new ; Step 8, use the opening obtained in step 7. α i_new ,flow Q i_new Yangcheng H i_new The data of the opening degree coordination working point located in the hump area is updated to obtain improved opening degree coordination working point data; Step 9: Obtain the optimized operating curve data of the pump operating condition based on Step 3 and Step 8. The optimized operating curve data includes the original cooperative opening condition point data outside the hump region and the updated cooperative opening condition point data within the hump region.

2. The method for increasing the input adjustment range of the pump in a variable-speed pumped storage unit according to claim 1, characterized in that, The safety margin in steps 2 and 5 is defined as the ratio of the head difference Hosm between the highest head margin point and the lowest point of the hump characteristic to the maximum operating head Hmaxps. The calculation formula can be written as: （3）。 3. The method for increasing the input adjustment range of the pump in a variable-speed pumped storage unit according to claim 1, characterized in that, The basis for determining that the operating point with the maximum flow rate in step 7 is the same as the operating point with the optimal efficiency is: under the same input conditions, the flow rate and efficiency of the pump in a pumped storage unit are directly proportional. The formula for calculating the pump efficiency is: （4）； In equation (4), η Represents efficiency. ρ Represents the density of water. g It represents gravitational acceleration.

Images