Electric energy conversion and switching system for multiple buses

Abstract

The invention provides an electric energy conversion and switching system for multiple buses in a thermal power plant. The frequency and / or the voltage of at least one connection end can be adjusted by an electric energy converter. Meanwhile, the electric energy is controlled to flow among the buses of the thermal power plant, wherein the buses are different in frequency. Or, the electric energy is controlled to flow among the buses of the thermal power plant, wherein the buses are the same in frequency or are different in frequency. Moreover, the throttling loss is reduced and even eliminated. The performance of a frequency-conversion generator set is fully played and the overall efficiency of the system is improved. As a result, the energy consumption is reduced and higher economic benefits are created. Meanwhile, a bus is divided into a plurality of segments for power supply, so that the running safety and the running reliability of the auxiliary machine of the frequency-conversion system are improved. In addition, through improving the motor starting and switching method of the auxiliary machine of the thermal power plant, the flexibility of the overall operation mode of the system is improved.

Description

technical field [0001] The invention relates to a multi-bus electric energy conversion and switching system, which can control the flow of electric energy between plant buses of different frequencies in a thermal power plant, or can control electric energy at different frequencies and control electric energy at the same frequency The flow between the plant busbars can help the electric motors of the plant auxiliary machines of the thermal power plant to start and / or switch. Background technique [0002] Energy conservation and emission reduction are not only the external requirements put forward by the state and society for thermal power plants, but also the internal requirements for thermal power plants to reduce costs, increase profits, and fulfill social responsibilities. Therefore, thermal power plants are actively tapping internal potentials and carrying out energy-saving transformation , innovative design, or adopt new technologies and new equipment, do everything poss...

AI Technical Summary

Problems solved by technology

[0003] However, the existing centralized frequency conversion power supply technology also has certain shortcomings: on the one hand, throttling loss occurs

In order to match the power imbalance between the two, and to meet the power and frequency required by the electric motor of the plant auxiliary machine under the working condition of the main steam turbine generator set, it is necessary to rely on adjusting the opening of the steam inlet regulating valve of the small steam turbine. Help to adjust the operating pressure of the small steam turbine to achieve the purpose of adjusting the speed and output power of the small steam turbine, resulting in throttling loss

[0004] In the second case, due to the design margin of the extraction steam source of the small steam turbine itself, or the adjustment of the operation mode, throttling loss will also occur

In the above cases, throttling loss will occur

[0005] On the other hand, the existing centralized frequency conversion power supply technology will restrict the flexibility of the system's operation mode, and the start-up and switching of the motors of the plant's auxiliary machines will be restricted.

It is reflected in: Generally, the motor of the plant auxiliary machine is directly started under the power frequency condition. In this starting mode, the starting current is relatively large, generally up to 4-7 times the rated current, which will reduce the life of the motor and affect the Other devices on the same bus have a greater impact, and the requirements for system capacity are relatively high

The motor of the factory auxiliary machine cannot complete the switching under the condition of frequency conversion

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