Coordination control method for speed regulator and converter in working condition conversion process of variable-speed pumped storage unit

Abstract

The invention relates to a coordination control method for a speed regulator and a converter in a working condition conversion process of a variable-speed pumped storage unit. Variable-speed pumped storage unit operation conditions are many, working condition conversion is frequent, the conversion process is complex, and reasonable working condition conversion control is of great importance to safe and stable operation of the unit. However, unlike conventional pumped storage units, the variable speed unit is commonly controlled by a governor and a converter. The relatively slow mechanical torque response characteristic of a guide vane-pump turbine system controlled by a speed regulator is not matched with the rapid electromagnetic torque response characteristic of a converter, and therefore working condition conversion control is more difficult. Therefore, the invention provides a corresponding flexible working condition conversion coordination control strategy which comprises four main stages of flexible self-starting, cut-in control, steady-state operation and cut-out control. In the working condition conversion transition process, the unit can safely, rapidly and softly achieveworking condition conversion by coordinating the speed regulator and the converter; all conversion stages are smoothly connected.

Description

technical field [0001] The invention relates to the field of pumped storage, in particular to a method for coordinated control of a governor and a converter in the process of switching working conditions of a variable-speed pumped-storage unit Background technique [0002] The double-fed variable-speed pumped storage unit is a new type of hydraulic energy storage-power generation system, which has the characteristics of high economy, large capacity, wide power adjustment range and fast speed. In the context of large-scale renewable energy access to the grid, variable speed units can undertake tasks such as peak shaving, valley filling, and frequency modulation, helping clean energy consumption, maintaining grid frequency stability, and improving grid stability. [0003] Variable speed pumped storage units have a wide variety of operating conditions, such as typical static, start-up, power generation, water pumping, synchronous phasing and spinning reserve, etc. It is usuall...

AI Technical Summary

Problems solved by technology

But in general, the existing research on the working condition conversion of the variable speed unit is limited to a single stage of the working condition conversion process, and has not studied the unit control method, dynamic response characteristics and the relationship between different stages from the overall process of the process. Smooth transitions are considered

This will lead to a single control strategy that cannot make the overall performance of the unit better

[0007] Although the complete working condition conversion control of the traditional pumped-storage unit has been reported, the structure, excitation mode and control method of the variable speed unit and the traditional unit are quite different, and the control method of the traditional unit cannot adapt to this unit.

All in all, there is still a lack of research on the coordinated control between the governor system and the converter system during the entire transition process of the variable speed unit.

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