Seaside power plant circulating water pump double-frequency-conversion energy-saving control system and method

Abstract

The invention discloses a seaside power plant circulating water pump double-frequency-conversion energy-saving control system and method. Based on circulating water pump frequency conversion transformation, protective control of circulating water mother pipe pressure is added, circulating water pump frequency conversion automatic control and circulating water pump outlet valve control loops are added, and a circulating water pump frequency conversion automatic protective control loop is arranged according to condenser vacuum, so that circulating water pump frequency conversion energy-saving automatic control is realized, the problem of multivariable cooperative control of sea level, circulating water inlet temperature, load and the like are solved, the automatic control level of the powerplant is increased, the electricity consumption of the circulating water pump is reduced and the energy-saving and consumption-reducing aims are fulfilled.

Description

technical field [0001] The invention relates to the field of automatic control of coal-fired power plants, in particular to a dual-frequency conversion energy-saving control system and method for circulating water pumps in seaside power plants. Background technique [0002] The cold end system of the steam turbine is relatively large, including the condenser and vacuum system, the circulating water system and the condensed water system, etc. There are many problems in it, which affect the thermal economy of the unit. The normal operation power consumption of each unit’s auxiliary equipment generally accounts for 5%-9% of the unit’s power generation. For seaside power plants, the power consumption of the circulating water pump in the cold-end system accounts for a considerable proportion of the plant’s power consumption. . Therefore, the energy-saving optimal control of the cold-end system can effectively achieve the purpose of energy-saving and consumption-reducing in therm...

AI Technical Summary

Problems solved by technology

[0007] 1. The cold-end system of conventional units uses a fixed-speed or double-speed circulating water pump, which can only be adjusted a limited number of times for long-term seasonal changes, and cannot effectively respond to changes in the temperature difference between day and night, and peak and valley changes in power loads;

[0008] 2. For seaside power plants, due to the influence of multiple variables such as tidal level, day and night / seasonal temperature, load, etc., the heat transfer performance of the condenser and the power consumption of the circulating water pump change at any time, and it is impossible to complete a more accurate cooling with only the experience of the operating personnel. End equipment control, lack of scientific guidance for controllable parameters such as unit start and stop in the actual operation process, parameter setting is blind, often because the pressure setting margin of the main pipe of the circulating pump is too large, resulting in serious waste of power consumption and energy of the circulating pump

On the one hand, seaside power plants are greatly affected by changes in tidal level, and the tidal level changes all the time. The operating status of each working condition is changing, and the operating characteristics of devices such as circulating pumps and condensers are changing, making it difficult to measure; secondly, the tidal level , ambient temperature, load and other variables, if you want to obtain more comprehensive data, the measurement workload is also a factor that needs to be considered

At the same time, due to the influence of fouling of cold-end pipes, there is a deviation between the actual operating conditions and the test conditions, which will also lead to inaccurate optimal control of the cold-end, and limited energy-saving effect

[0010] 4. According to the performance test, the parameters of the cold-end system are set, and the operation guidance table or curve is often used for guidance. The operator needs to perform interpolation and other optimization work on the current operating conditions to determine the relevant setting parameters. It is inconvenient to use and the operator labor intensive

When there are many variables at the same time, it is more unrealistic to perform parameter correction in real time

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