CN-122001031-A - Method, equipment and medium for actively supporting inertia of power grid by expansion generator set

Abstract

The invention discloses a method, a system, equipment and a medium for actively supporting the inertia of a power grid of an expansion generating set, which belong to the technical field of compressed air energy storage and comprise the steps of collecting voltage and current signals of the power grid in real time, calculating the frequency value of the power grid from the collected signals and obtaining power grid frequency data; the method comprises the steps of obtaining frequency difference and frequency change rate through differential calculation of obtained frequency data, calculating upper and lower limits of power grid moment of inertia and adjustable moment of inertia resources of a system in real time according to unit operation conditions in a regional power grid, calculating system moment of inertia allowance under the condition of maximum frequency difference and maximum frequency change rate according to the frequency difference and the frequency change rate, and controlling a compressed air energy storage unit to perform active adjustment based on calculation results. The invention realizes inertia support, can quickly respond to the frequency fluctuation of the power grid, enhances the frequency stability of the regional power grid, improves the acceptance of the regional power grid to renewable energy sources, and ensures the safe and reliable operation of the power grid.

Inventors

• WEN XIANKUI
• HU QUAN
• MA XINHUI
• ZHONG JINGLIANG
• HE MINGJUN
• WU YINGHAO
• An Yuanyun
• TIAN JIAYIN
• WANG SUOBIN
• ZHOU KE
• FAN QIANG
• YE HUAYANG
• ZHANG SHIHAI
• LI BOWEN
• PANG LINGRONG
• FAN LEI
• CHEN JUNWEI

Assignees

• 贵州电网有限责任公司

Dates

Publication Date

20260508

Application Date

20251225

Claims (10)

1. 1. A method for actively supporting the inertia of a power grid by an expansion generating set is characterized by comprising the following steps of, Installing a power grid monitoring unit, collecting voltage and current signals of a power grid in real time, calculating a frequency value of the power grid from the collected signals, and obtaining power grid frequency data; obtaining a frequency difference and a frequency change rate by carrying out differential calculation on the obtained frequency data; According to the running condition of a unit in the regional power grid, calculating the rotational inertia of the power grid and the upper limit and the lower limit of the adjustable rotational inertia resource of the system in real time; Calculating the system moment of inertia allowance under the maximum frequency difference condition and the maximum frequency change rate according to the frequency difference and the frequency change rate; and controlling the compressed air energy storage unit to perform active adjustment based on the calculation result.
2. 2. The method for actively supporting the inertia of the power grid by the expansion generating set according to claim 1, wherein the calculating the frequency value of the power grid comprises the steps of installing a high-precision power grid monitoring unit at a power grid interface, accessing the power grid through a voltage transformer and a current transformer, and collecting voltage and current signals of the power grid in real time; the frequency value of the power grid is calculated from the acquired signals using a fourier transform algorithm.
3. 3. The method for actively supporting the inertia of the power grid of the expansion generating set according to claim 2, wherein the differential calculation comprises the steps of sending a frequency signal to a frequency difference and frequency change rate calculation module to calculate a frequency difference after the power grid frequency acquisition module acquires the power grid frequency value And rate of change of frequency The relation between the frequency difference and the frequency change rate is: Wherein, the As a function of the frequency rate of change over time.
4. 4. The method for actively supporting the inertia of the power grid by the expansion generating set according to claim 3, wherein the calculating the moment of inertia of the power grid in real time and the upper and lower limits of the system adjustable moment of inertia resources comprise calculating the moment of inertia of the system in real time, wherein the moment of inertia is calculated by the following formula: Wherein, the Is the rated power of the ith thermal power generating unit, Is the inertia time constant of the ith thermal power generating unit, The start-stop coefficient of the ith thermal power generating unit is 1 when the thermal power generating unit is started and 0 when the thermal power generating unit is stopped; The rated power of the j new energy unit, Is the inertia time constant of the jth new energy unit, The start-stop coefficient of the j new energy unit is 1 when the new energy unit is started and 0 when the new energy unit is stopped; is the rated power of the L-th CAES expansion unit, Is the inertia time constant of the L-th CAES expansion machine set, The start-stop coefficient of the L-th CAES expansion unit is 1, the start-stop coefficient is 0;n, the number of thermal power units is 0;n, the number of new energy units is m, s is the number of CAES expansion units in the regional power grid, and i, j and L are variable indexes respectively; And calculating the upper limit and the lower limit of adjustable inertia resources of the regional power grid system, wherein the upper limit is equal to the rotational inertia of the system when all units in the power grid are in full operation, and the lower limit is equal to the rotational inertia of the system after all the compressed air units are out of operation.
5. 5. A method for actively supporting grid inertia for an expansion generating set according to claim 4, wherein calculating a system moment of inertia margin for maximum frequency difference and maximum rate of frequency change comprises, at At the moment, no frequency difference occurs, at the moment, the system has active disturbance, and the frequency change rate is maximum, so that the system independently meets the system inertia of the frequency maximum change rate which can be born by the system The method comprises the following steps: Wherein, the For the active power disturbance of the system, Is that The frequency change rate at the moment, namely the maximum frequency change rate of the system; At the position of At the moment, the frequency difference is maximum, and at the moment, the frequency change rate is 0, so that the system independently meets the system inertia of the maximum frequency difference which can be born by the system The method comprises the following steps: Wherein, the To individually satisfy the system inertia of the maximum frequency difference that the system can withstand, For the system primary frequency modulation droop coefficient, Is used as a damping coefficient of the system, Is the comprehensive influencing parameter of the mechanical characteristics and the frequency response of the system of the thermal power generating unit/the compressed air energy storage unit, For the time constant of the dynamic response of the synchronous machine generator frequency modulator in the system, For the damping ratio of the frequency response process of the system over time, Is the natural frequency in the dynamic frequency response process.
6. 6. The method for actively supporting the inertia of a power grid by an expansion power generating set according to claim 5, wherein calculating the margin of the system moment of inertia under the conditions of maximum frequency difference and maximum frequency change rate further comprises defining the system requirement inertia The method comprises the following steps: At the position of The active disturbance occurs at the moment, and the frequency change rate is the largest; For the moment when the frequency difference reaches the maximum, calculating the system inertia allowance under the condition of the maximum frequency change rate and the maximum frequency difference : When (when) When the power is more than or equal to 0, the allowance of the system is sufficient, the inertia requirement of the system is met, the thermal power unit adjusts the output according to the active deviation, the active is output to the system or reduced, and the adjustment frequency difference stabilizes the system; When (when) <0, Indicating that the system margin is insufficient, the existing inertia does not meet the real-time requirement of the system inertia, and starting the compressed air energy storage unit at the moment, and when the system inertia margin is the same And after the power is more than or equal to 0, the compressed air energy storage unit adjusts the active power again to eliminate the active disturbance.
7. 7. The method for actively supporting the inertia of a power grid for an expansion power generating set according to claim 6, wherein calculating a system moment of inertia margin for a maximum frequency difference and a maximum rate of frequency change further comprises defining a system moment of inertia margin The method comprises the following steps: the range of the inertia adequacy of the system is selected to be 0< ≤1%; When (when) Under the working condition <0 >, the system starts the compressed air energy storage unit, so that the compressed air energy storage unit is used for adjusting the frequency difference by preferentially modulating the frequency after the real-time inertia meets the system demand inertia; According to the number of running compressed air energy storage units in the regional power grid, determining a corresponding active adjustment weighting proportion according to the current rated installed capacity, and calculating the weight as follows: Wherein, the The weight is adjusted for the active power of the L-th CAES unit, And x is the number of CAES units started by adjusting the moment of inertia in the system, and x is more than or equal to 1 and less than or equal to x < s.
8. 8. A method for actively supporting grid inertia of an expansion power generating set according to claim 7, wherein controlling the active power adjustment of the compressed air energy storage unit comprises the active power adjustment of the compressed air energy storage unit The method comprises the following steps: When (when) When not less than 0, judging that the adequacy is 0< The condition of less than or equal to 1 percent is satisfied; If the adequacy is 0< The condition of less than or equal to 1 percent is not satisfied, the CAES units are sequentially cut off from small to large according to the active adjustment weight coefficient sequencing of the CAES units until the adequacy is 0< The condition of less than or equal to 1 percent is satisfied.
9. 9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, carries out the steps of a method of actively supporting the inertia of a power grid of an expansion power generating set according to any of claims 1 to 8.
10. 10. A computer readable storage medium having stored thereon a computer program, which when executed by a processor, implements the steps of a method of actively supporting grid inertia for an expansion power generating set according to any of claims 1 to 8.

Description

Method, equipment and medium for actively supporting inertia of power grid by expansion generator set Technical Field The invention relates to the technical field of compressed air energy storage, in particular to a method, equipment and medium for actively supporting inertia of a power grid by an expansion generating set. Background In recent years, the use of renewable energy sources such as wind energy and solar energy in electric power systems has been rapidly increasing. The energy sources are connected into a power grid through the power electronic converter, so that the clean energy sources are utilized efficiently, but the mechanical moment of inertia of the traditional synchronous generator is lacked. Meanwhile, a Compressed Air Energy Storage (CAES) system is taken as a large-scale energy storage technology, has the advantages of large energy storage scale, long storage period, small environmental pollution and the like, and is considered as one of the large-scale energy storage technologies with the most development prospect. In the traditional CAES system, a compressor is driven by a motor to consume electric energy of a power grid in a compression stage, and high-pressure air drives an expander to drive a generator to generate electricity in an energy release stage. However, current CAES systems have not fully exploited their potential in grid frequency regulation. The novel energy power supply points are connected in a large scale, the regional power grid inertia level is reduced, so that the stability of the system is weakened when the system is disturbed, the power grid frequency fluctuation risk is aggravated, the conventional thermal power generating unit has a delayed frequency modulation response, meanwhile, the unit is in a peak regulation running state for a long time, the requirement of rapid frequency support of the power grid is difficult to meet, in addition, the research focus of the conventional CAES expansion generator is mainly power output control, frequency regulation and the like, and the inertia potential development of the rotating parts of the conventional CAES expansion generator is still in an initial stage. In order to improve the stability of regional power grids, a technical scheme capable of providing adjustable moment of inertia support for the power grid when the inertia of the power grid changes by using a CAES system needs to be developed. The technology can solve the problems that in the prior art, the regional power grid has low inertia and poor frequency stability due to the fact that renewable energy is connected, and the thermal power unit is slow in response, so that inertia support cannot be effectively realized. Therefore, there is a need for a solution that can provide adjustable moment of inertia support for the grid when the grid inertia changes using the CAES system. Disclosure of Invention The present invention has been made in view of the above-described problems. Therefore, the invention aims to solve the problems that in the prior art, the regional power grid has low inertia, poor frequency stability and slow response of a thermal power unit, and the inertia support cannot be effectively realized due to the fact that renewable energy sources are connected. According to the invention, under the double constraints of frequency deviation and frequency change rate, when new energy sources such as wind and light generate fluctuation, the running state of the expansion generator is adjusted by utilizing the rapid starting and adjusting characteristics of compressed air energy storage, so that the moment of inertia of the expansion generator after the running state adjustment meets the requirement index. In order to solve the technical problems, the invention provides a method for actively supporting the inertia of a power grid by an expansion generating set, which comprises the following steps of, The method comprises the steps of installing a power grid monitoring unit, collecting voltage and current signals of a power grid in real time, calculating frequency values of the power grid from the collected signals, obtaining power grid frequency data, obtaining frequency differences and frequency change rates through differential calculation of the obtained frequency data, calculating upper and lower limits of power grid moment of inertia and adjustable moment of inertia resources of a system in real time according to unit operation conditions in a regional power grid, calculating a system moment of inertia allowance under the condition of maximum frequency differences and maximum frequency change rates according to the frequency differences and the frequency change rates, and controlling a compressed air energy storage unit to conduct active adjustment based on calculation results. The method for actively supporting the inertia of the power grid by the expansion generating set comprises the following steps of calculating the frequency value of the power