Low-frequency load shedding control method considering primary frequency modulation and load priority

Abstract

The invention discloses a low-frequency load shedding control method considering primary frequency modulation and load priority, and the method comprises the following steps: S1, frequency change: calculating a frequency offset and a frequency change rate, and setting a frequency drop threshold value; s2, calculating power vacancy: according to the frequency change rate obtained in the step S1, solving the power vacancy according to the fact that the power vacancy is in direct proportion to the frequency change rate; s3, aggregating the temperature control load with response capability, such as an air conditioner and a water heater, calculating satisfaction degree pairs of the temperature control load according to the operation state of the temperature control load, and sequencing the satisfaction degrees; s4, selecting a low-frequency load shedding scheme; the method has the advantages that compared with traditional low-frequency load shedding, the controllable temperature control load is subjected to power utilization priority ranking, the influence on the user side is reduced to the minimum, and when a power grid is disturbed, the frequency can be recovered to an allowable range within a short time.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a low-frequency load-shedding control method taking primary frequency regulation and load priority into consideration. Background technique [0002] The frequency in the power system is determined by the active power generated by the generator and the active power required by the load. Frequency is an important indicator of power quality. With the large-scale development of wind power and photovoltaics, the power system's ability to support frequency becomes weaker. In the construction of UHV AC and DC projects, once DC blockage occurs, it will cause a serious power shortage. If it cannot be controlled in time, it will cause a rapid drop in frequency, which will further lead to system disconnection. Emergency control devices for frequency and voltage constitute a power The third line of defense of the system. When there is a serious power shortage in the power system, low-f...

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Problems solved by technology

[0002] The frequency in the power system is determined by the active power generated by the generator and the active power required by the load. Frequency is an important indicator of power quality. With the large-scale development of wind power and photovoltaics, the power system's ability to support frequency becomes weaker. In the construction of UHV AC and DC projects, once DC blockage occurs, it will cause a serious power shortage. If it cannot be controlled in time, it will cause a rapid drop in frequency, which will further lead to system disconnection. Emergency control devices for frequency and voltage constitute a power The third line of defense of the system. When there is a serious power shortage in the power system, low-frequency load shedding is required for system collapse and large-scale power outages. For traditional power cuts, load-side users’ tolerance for power outages performance decline, unable to meet the normal electricity demand of users, so it is necessary to improve the existing low-frequency load shedding scheme;

[0003] The current low-frequency load shedding is to cut off the load and lines to reduce the power shortage and increase the frequency. In fact, the controllable load is not just some lines, but a ubiquitous controllable load. At present, there are low-frequency load shedding and intelligent The combination of home appliances uses active response loads instead of passive load shedding to minimize the amount of load shedding and reduce the impact on users, but does not take into account the priority of controllable loads such as smart home appliances, and does not consider the primary frequency adjustment Function, regardless of the primary frequency adjustment of the generator will lead to over-cutting of the load, and the spinning reserve cannot be fully utilized. There is also a certain delay when the controllable load provides response power, which will affect the frequency change

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