Method and system for improving power factor of total reduced 220KV receiving port

Abstract

The invention discloses a method and system for improving a total-drop 220KV receiving port power factor, and the method is characterized in that the method comprises the following steps: centralized compensation: enabling the power factor of the high-voltage side of a transformer substation to reach a preset target value through adjusting the transformer gear of the transformer substation and setting a reactive compensation device switching scheme; decentralized compensation: adjusting multiple reactive power of the 150MW generator set and adjusting the power factor of the generator; in-situ compensation: controlling a reactive power output mode of the grid-connected generator set, and switching a plurality of groups of generators from constant voltage operation to constant reactive power operation so as to increase reactive power supply of the system; and the power factor of the high-voltage receiving port of the total step-down transformer substation is increased to be greater than a target threshold value through cooperative control of centralized compensation, decentralized compensation and in-situ compensation. The method can improve the power factor of a power grid, reduces the loss of equipment such as a transformer and a power transmission line, achieves the purposes of reducing cost and increasing efficiency, and is good in use effect and convenient to popularize and use.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, in particular to a method and system for improving the power factor of a 220KV receiving port. Background Art

[0002] After the 150MW generator set is connected to the grid, the 220KV power supply often sees a decrease in the amount of purchased active power, or power is fed back to the system. In these two cases, the power factor will become very low, with the purchased active power being less than the purchased reactive power, or the fed-back active power (the fed-back active power is smaller) being less than the purchased reactive power, resulting in a low power factor. A low power factor can lead to many problems, such as: (1) The smaller the power factor of the power-consuming enterprise, the greater its apparent power. To meet the power demand, the capacity of the power supply line and transformer will also be larger. This will not only increase power supply investment and reduce equipment utilization, but also increase line network losses. (2) The apparent power transmitted by the line remains unchanged, and the lower power factor increases the power loss within the transformer and related electrical equipment network, directly increasing the cost of electricity. (3) When the power factor is low, the voltage of the equipment changes greatly, the reactive power loss is also large, the equipment ages faster, and it is easy to shorten the service life of the equipment, affect the operation of the equipment, increase safety problems and greatly reduce the original design life of the equipment. Equipment maintenance and production stoppage due to equipment failure will cause serious economic losses to the company. Summary of the Invention

[0003] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method and system for improving the power factor of a total 220KV receiving port, which can improve the power factor of the power grid and reduce the losses of transformers and transmission line equipment to solve the problems raised by the above-mentioned background technology.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for improving the power factor of a total 220KV receiving port, comprising the following steps:

[0005] Centralized compensation: By adjusting the transformer gear of the substation and setting the switching plan of the reactive compensation device, the power factor on the high-voltage side of the substation can reach the preset target value;

[0006] Distributed compensation: adjust the reactive power of 150MW generator sets and adjust the power factor of the generators;

[0007] On-site compensation: Control the reactive power output mode of the grid-connected generator sets, switching multiple generator sets from constant voltage operation to constant reactive power operation to increase the reactive power supply of the system;

[0008] Through the coordinated control of centralized compensation, decentralized compensation and local compensation, the power factor of the high-voltage receiving port of the total step-down substation is increased to greater than the target threshold.

[0009] As a further improvement of the present invention: the adjusting the operating parameters of the substation transformer includes:

[0010] Real-time data collection of transformer high-voltage or low-voltage side voltage, power factor, load current, and reactive power demand data is performed, and the output voltage is adjusted by changing the transformer tap position.

[0011] As a further improvement of the present invention: in the centralized compensation, the step of setting the switching scheme of the reactive compensation device includes:

[0012] When the transformer is at peak load, the power factor on the high-voltage side of the transformer is less than the first power factor threshold, and multiple sets of reactive power compensation devices are put into operation;

[0013] When the transformer is in a valley load state, the power factor on the high-voltage side of the transformer is greater than a first power factor threshold, and the plurality of reactive compensation devices are cut off.

[0014] As a further improvement of the present invention: in the centralized compensation, the step of setting the switching scheme of the reactive compensation device further includes:

[0015] When the transformer is at peak or valley load, if the transformer reactive power is reversed, multiple groups of reactive compensation devices are cut off;

[0016] When the transformer is in a shutdown state, all reactive compensation devices are cut off.

[0017] As a further improvement of the present invention: the first power factor threshold is 0.95, and when the voltage on the low-voltage side of the transformer is higher than the second voltage threshold, multiple groups of reactive compensation devices are cut off to maintain voltage stability, and the second voltage threshold is 10.8KV.

[0018] As a further improvement of the present invention: the dispersion compensation includes:

[0019] When the voltage on the low-voltage side of the transformer is 10KV and the power factor is less than 0.9, the reactive power compensation device is put into operation to maintain the system voltage at 10.5KV and the power factor greater than 0.9.

[0020] As a further improvement of the present invention, the process of adjusting the excessive reactive power of the 150MW generator set includes:

[0021] Adjust the winding temperature and core temperature of the 150MW generator set to less than 130°C. When the winding temperature and core temperature approach 130°C, reduce the reactive output of the generator set and put the reactive compensation device into use;

[0022] When the generator load is 150MW or above, the stator voltage is controlled to be greater than 16.2kV. The stator voltage is increased while ensuring the stability of the power system.

[0023] When the generator set load is between 130MW and 150MW, the generator set stator voltage controls the power factor at a minimum of 16.45kV to ensure that the power factor is not less than 0.9. When the power system is stable, the stator voltage is increased;

[0024] When the generator set load is 130MW or below, the generator set stator voltage is controlled at 16.54kV. When the power system is stable, the stator voltage is increased.

[0025] As a further improvement of the present invention: in the on-site supplementation, configuring a reactive power compensation device on the distribution side includes:

[0026] Adjust the reactive power output of the generator, sintering waste heat generator, and saturated steam generator to compensate for the reactive power of the 10KV system.

[0027] As a further improvement of the present invention: the reactive output of the adjustment generator, sintering waste heat generator, and saturated steam generator includes:

[0028] The constant reactive power output of the generator was adjusted from 2000Kvar to 3000Kvar; the constant voltage output mode of the sintering waste heat generator and saturated steam generator was changed to constant reactive power output mode.

[0029] In another aspect, the present invention provides a system for improving the power factor of a 220 kV receiving port, comprising:

[0030] Centralized compensation: By adjusting the operating parameters of the substation transformer and dynamically controlling the switching of reactive power compensation devices based on load conditions, the power factor on the high-voltage side of the substation reaches the preset target value;

[0031] Distributed compensation: Configure reactive power compensation devices on the distribution side and dynamically adjust the compensation capacity based on real-time power factor detection results;

[0032] On-site compensation: Control the reactive power output mode of the grid-connected generator sets, switching multiple generator sets from constant voltage operation to constant reactive power operation to increase the reactive power supply of the system;

[0033] Through the coordinated control of centralized compensation, decentralized compensation and local compensation, the power factor of the high-voltage receiving port of the total step-down substation is increased to above the target threshold.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The method of the present invention for improving the power factor of a 220kV receiving port of a total step-down substation improves the power factor of the 220kV receiving port of the high-voltage receiving port of the total step-down substation from the original 0.67 to above 0.9 through the coordinated control of centralized compensation, decentralized compensation and local compensation. The method is simple, reasonably designed, and easy to implement. It can improve the power factor of the power grid, reduce the loss of equipment such as transformers and transmission lines, and achieve the purpose of reducing costs and increasing efficiency. It has good use effect and is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0037] In order to enable a clear and complete understanding of the technical solution, the present invention is further described in conjunction with the embodiments and drawings. Obviously, the described embodiments are only some embodiments of the present invention, and all other embodiments obtained by technical personnel in the relevant field without making creative work are within the scope of protection of the present invention.

[0038] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0039] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0040] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0041] An embodiment of the present invention provides a method for improving the power factor of a 220 kV receiving port, comprising the following steps:

[0042] Centralized compensation: By adjusting the transformer gear of the substation and setting the switching plan of the reactive compensation device, the power factor on the high-voltage side of the substation can reach the preset target value;

[0043] Distributed compensation: adjust the reactive power of 150MW generator sets and adjust the power factor of the generators;

[0044] On-site compensation: Control the reactive power output mode of the grid-connected generator sets, switching multiple generator sets from constant voltage operation to constant reactive power operation to increase the reactive power supply of the system;

[0045] Through the coordinated control of centralized compensation, decentralized compensation and local compensation, the power factor of the high-voltage receiving port of the total step-down substation is increased to greater than the target threshold.

[0046] According to the method of improving the power factor of a total step-down 220KV receiving port of the present application, the present application improves the power factor of the 220kV receiving port of the high-voltage receiving port of the total step-down substation from the original 0.67 to above 0.9 through the coordinated control of centralized compensation, decentralized compensation and local compensation. Specifically, a centralized compensation method is adopted to optimize the reactive balance on the high-voltage side through transformer tap adjustment and dynamic switching of capacitor groups. A decentralized compensation method is adopted to configure SVG / capacitor groups on the 10kV side to compensate for the reactive gap on the distribution side in real time. An on-site compensation method is adopted to improve the reactive output capacity of 150MW units and auxiliary generator sets. The method is simple, reasonably designed, and easy to implement. It can improve the power factor of the power grid, reduce the loss of equipment such as transformers and transmission lines, and achieve the purpose of reducing costs and increasing efficiency. It has good use effect and is easy to promote and use.

[0047] In one embodiment of the present invention, adjusting the operating parameters of the substation transformer includes:

[0048] Real-time data collection of transformer high-voltage or low-voltage side voltage, power factor, load current, and reactive power demand data is performed, and the output voltage is adjusted by changing the transformer tap position.

[0049] Furthermore, in the centralized compensation, the step of setting a switching plan for the reactive compensation device includes:

[0050] When the transformer is at peak load, the power factor on the high-voltage side of the transformer is less than the first power factor threshold, and multiple sets of reactive power compensation devices are put into operation;

[0051] When the transformer is in a valley load state, the power factor on the high-voltage side of the transformer is greater than a first power factor threshold, and the plurality of reactive compensation devices are cut off.

[0052] Furthermore, in the centralized compensation, the step of setting the switching plan of the reactive compensation device further includes:

[0053] When the transformer is at peak or valley load, if the transformer reactive power is reversed, multiple groups of reactive compensation devices are cut off;

[0054] When the transformer is in a shutdown state, all reactive compensation devices are cut off.

[0055] In this embodiment, by collecting data such as voltage and power factor in real time, the transformer ratio is adjusted to optimize the bus voltage and reduce the reactive power demand of inductive loads. Furthermore, since the power factor is inversely proportional to the system's reactive power, providing capacitive reactive power through the compensation device can reduce the system's total reactive power demand, thereby improving the power factor. During peak loads, when the power factor is less than 0.95, the reactive power compensation device is activated. During off-peak loads, when the power factor is greater than 0.95, the reactive power compensation device is removed, dynamically matching reactive power supply and demand.

[0056] Furthermore, when the voltage on the low-voltage side of the transformer exceeds the second voltage threshold, multiple groups of reactive compensation devices are disconnected to maintain voltage stability. The second voltage threshold is 10.8kV. Centralized compensation includes the unified coordination and management of the switching on and off of reactive compensation devices at each station. When the system voltage is higher than 10.8kV, no power factor needs to be considered, and some reactive compensation devices need to be reasonably withdrawn until the system voltage is maintained at around 10.5kV. When the voltage on the low-voltage side is greater than 10.8kV, the capacitor group is disconnected first, even if the power factor does not meet the standard, to prevent overvoltage. When reactive reverse flow is detected, the compensation device is immediately disconnected to avoid reverse reactive flow and voltage instability. A dynamic balance is achieved between power factor optimization and voltage stability to meet the dual needs of grid security and economic operation.

[0057] In one embodiment of the present invention, the dispersion compensation includes:

[0058] When the voltage on the low-voltage side of the transformer is 10KV and the power factor is less than 0.9, the reactive power compensation device is put into operation to maintain the system voltage at 10.5KV and the power factor greater than 0.9.

[0059] When the transformer's low-voltage side voltage is 10kV and the power factor is below 0.9, reactive power compensation devices are activated to maintain the system voltage at 10.5kV and raise the power factor to above 0.9. This reduces power consumption, line current, and thus line losses. Stabilizing the voltage at 10.5kV prevents motor overheating and insufficient torque due to undervoltage, extending equipment life.

[0060] In one embodiment of the present invention, the process of adjusting the excessive reactive power of the 150MW generator set includes:

[0061] Temperature control: adjust the winding temperature and core temperature of the 150MW generator set to less than 130℃. When the winding temperature and core temperature approach 130℃, reduce the generator set reactive output and put the reactive compensation device into use. Monitor the winding temperature and core temperature of the generator set in real time to ensure that they do not exceed 130℃. When the temperature approaches this threshold, adjust it immediately.

[0062] When the load of the generator set is 150MW and above, the stator voltage is controlled to be greater than 16.2kV, and the stator voltage is increased while ensuring the stability of the power system. When the load of the unit is ≥150MW, the lower limit of the stator voltage is set to 16.2kV, and the voltage is increased as much as possible under the basic principle of stable generator set temperature. Increasing the stator voltage can significantly increase reactive output, and the increased voltage reduces line current and line losses.

[0063] When the load of the generator set is between 130MW and 150MW, the stator voltage of the generator set controls the power factor at a minimum of 16.45kV to ensure that the power factor is not less than 0.9. Under the condition of meeting the stability of the power system, the stator voltage is increased; when the load is 130-150MW, 16.45kV is used as the lower limit of the stator voltage to ensure that the power factor is ≥0.9. Under the basic principle, the voltage is increased as much as possible under the premise of stable generator set temperature. Increasing the stator voltage can significantly increase reactive power output. The increase in voltage reduces line current and line loss. Through voltage regulation and power factor threshold control, the reactive power supply and demand balance is maintained while ensuring active power output.

[0064] When the generator set load is 130MW or less, the generator set stator voltage is controlled at 16.54kV. The stator voltage can be increased while ensuring power system stability. When the load is ≤130MW, the stator voltage is set at 16.54kV as the lower limit, and the voltage is adjusted as high as possible while ensuring stable generator set temperature. Increasing the stator voltage can significantly increase reactive power output. This voltage increase reduces line current and line losses. At low loads, system inertia is low, and maintaining a higher voltage can avoid the risk of voltage collapse caused by reactive power shortages.

[0065] In this embodiment, first, the winding and core temperature is monitored in real time. When it approaches 130°C, the reactive output is automatically reduced and the compensation device is activated to avoid insulation aging or equipment burning due to overheating. Then, different stator voltage lower limits are set according to the load range to prevent winding current overload caused by low voltage operation and reduce the risk of grid oscillation. In addition, the temperature and voltage are adjusted in a linked manner to avoid the dual risks of equipment overload and voltage instability.

[0066] In one embodiment of the present invention, in the on-site supplementation, configuring a reactive power compensation device on the distribution side includes:

[0067] Adjust the reactive power output of the generator, sintering waste heat generator, and saturated steam generator to compensate for the reactive power of the 10KV system.

[0068] Furthermore, the reactive output of the adjustment generator, sintering waste heat generator, and saturated steam generator includes:

[0069] The constant reactive power output of the generator was adjusted from 2000Kvar to 3000Kvar; the constant voltage output mode of the sintering waste heat generator and saturated steam generator was changed to constant reactive power output mode.

[0070] In this embodiment, by optimizing the generator operating mode and improving reactive power output, the reactive power compensation capability on the 10kV distribution side is systematically enhanced. The generator's constant reactive power output increases from 2000 kvar to 3000 kvar, a 50% improvement. This constant reactive power output provides stable support and prevents voltage drops caused by sudden load changes. The sintering waste heat generator and saturated steam generator switch from constant voltage mode to constant reactive power mode, actively outputting reactive power to offset the reactive power demand of inductive loads on the distribution side and reduce voltage fluctuations.

[0071] In another aspect, the present invention provides a system for improving the power factor of a 220 kV receiving port, comprising:

[0072] Centralized compensation: By adjusting the operating parameters of the substation transformer and dynamically controlling the switching of reactive power compensation devices based on load conditions, the power factor on the high-voltage side of the substation reaches the preset target value;

[0073] Distributed compensation: Configure reactive power compensation devices on the distribution side and dynamically adjust the compensation capacity based on real-time power factor detection results;

[0074] On-site compensation: Control the reactive power output mode of the grid-connected generator sets, switching multiple generator sets from constant voltage operation to constant reactive power operation to increase the reactive power supply of the system;

[0075] Through the coordinated control of centralized compensation, decentralized compensation and local compensation, the power factor of the high-voltage receiving port of the total step-down substation is increased to above the target threshold.

[0076] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical solutions and technical concepts of the present invention without creative mental work, and all of them fall within the scope of protection of the present invention.

Claims

1. A method for improving the power factor of a 220KV receiving port, characterized in that: The following steps are involved: Centralized compensation: By adjusting the transformer gear of the substation and setting the switching plan of the reactive compensation device, the power factor on the high-voltage side of the substation can reach the preset target value; Distributed compensation: adjust the reactive power of 150MW generator sets and adjust the power factor of the generators; On-site compensation: Control the reactive power output mode of the grid-connected generator sets, switching multiple generator sets from constant voltage operation to constant reactive power operation to increase the reactive power supply of the system; Through the coordinated control of centralized compensation, decentralized compensation and local compensation, the power factor of the high-voltage receiving port of the total step-down substation is increased to greater than the target threshold.

2. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: The adjusting the operating parameters of the substation transformer includes: Real-time data collection of transformer high-voltage or low-voltage side voltage, power factor, load current, and reactive power demand data is performed, and the output voltage is adjusted by changing the transformer tap position.

3. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: In the centralized compensation, the step of setting a switching plan for a reactive compensation device includes: When the transformer is at peak load, the power factor on the high-voltage side of the transformer is less than the first power factor threshold, and multiple sets of reactive power compensation devices are put into operation; When the transformer is in a valley load state, the power factor on the high-voltage side of the transformer is greater than a first power factor threshold, and the plurality of reactive compensation devices are cut off.

4. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: In the centralized compensation, the step of setting a switching plan for a reactive compensation device further includes: When the transformer is at peak or valley load, if the transformer reactive power is reversed, multiple groups of reactive compensation devices are cut off; When the transformer is in a shutdown state, all reactive compensation devices are cut off.

5. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: The first power factor threshold is 0.95, and when the voltage on the low-voltage side of the transformer is higher than the second voltage threshold, multiple groups of reactive compensation devices are cut off to maintain voltage stability. The second voltage threshold is 10.8KV.

6. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: The dispersion compensation includes: When the voltage on the low-voltage side of the transformer is 10KV and the power factor is less than 0.9, the reactive power compensation device is put into operation to maintain the system voltage at 10.5KV and the power factor greater than 0.

9.

7. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: The process of adjusting the excessive reactive power of the 150MW generator set includes: Adjust the winding temperature and core temperature of the 150MW generator set to less than 130°C. When the winding temperature and core temperature approach 130°C, reduce the reactive output of the generator set and put the reactive compensation device into use; When the generator load is 150MW or above, the stator voltage is controlled to be greater than 16.2kV. The stator voltage is increased while ensuring the stability of the power system. When the generator set load is between 130MW and 150MW, the generator set stator voltage controls the power factor at a minimum of 16.45kV to ensure that the power factor is not less than 0.

9. When the power system is stable, the stator voltage is increased; When the generator set load is 130MW or below, the generator set stator voltage is controlled at 16.54kV. When the power system is stable, the stator voltage is increased.

8. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: In the on-site supplementation, configuring a reactive power compensation device on the distribution side includes: Adjust the reactive power output of the generator, sintering waste heat generator, and saturated steam generator to compensate for the reactive power of the 10KV system.

9. The method for improving the power factor of a 220KV receiving port according to claim 1, characterized in that: The reactive output of the adjustment generator, sintering waste heat generator, and saturated steam generator includes: The constant reactive power output of the generator was adjusted from 2000Kvar to 3000Kvar; the constant voltage output mode of the sintering waste heat generator and saturated steam generator was changed to constant reactive power output mode.

10. A system for improving the power factor of a 220KV receiving port, characterized in that: The method for improving the power factor of a 220 kV receiving port according to any one of claims 1 to 9 further comprises: Centralized compensation module: By adjusting the operating parameters of the substation transformer and dynamically controlling the switching of reactive power compensation devices based on load conditions, the power factor on the high-voltage side of the substation reaches the preset target value; Distributed compensation module: A reactive compensation device is configured on the distribution side to dynamically adjust the compensation capacity based on real-time power factor detection results; On-site compensation module: controls the reactive power output mode of the grid-connected generator sets, switching multiple generator sets from constant voltage operation to constant reactive power operation to increase the reactive power supply of the system; The controller, through the coordinated control of centralized compensation, decentralized compensation and local compensation, increases the power factor of the high-voltage receiving port of the main step-down substation to above the target threshold.

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