Pumped-Storage Control Apparatus for Speed Variation Suppression
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Solution Overview
Problem
Conventional control apparatuses for adjustable-speed, pumped-storage power plants face challenges in suppressing excessive variations in revolving speed during rapid changes in power command values or flow rates, leading to potential out-of-range revolving speeds and the need for increased excitation capacity, which affects economy and efficiency.
Innovation Solution
A power generation system control apparatus that includes a revolving speed control signal generator, a guide vane control signal generator, and an adder, utilizing a two-step differentiation circuit to adjust guide vane opening commands, thereby generating servo control signals that effectively manage revolving speed variations and reduce excitation capacity requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If guide vanes are opened quickly to increase pump turbine flow rate, then response speed is improved, but excessive revolving speed variation occurs
Solution Approach 1:
The control apparatus calculates a preliminary guide vane opening command value based on the effective head and power command value before actual valve operation. This preliminary calculation anticipates the required opening degree to achieve desired power output while considering current hydraulic conditions, preventing excessive revolving speed variation by pre-planning the optimal valve position rather than reacting to power deficits after they occur.
Solution Approach 2:
The control apparatus continuously monitors the effective head and compares it with the calculated guide vane opening command value. By feeding back the actual effective head condition to the control system, the apparatus dynamically adjusts the guide vane opening to maintain optimal revolving speed, ensuring that rapid openings do not cause excessive speed variations while still achieving quick response to power commands.
2Reliability
If excitation capacity is increased to handle revolving speed variations, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The control apparatus replaces the need for oversized mechanical excitation capacity with a sophisticated control system that uses sensors, calculators, and actuators to manage revolving speed variations. Instead of relying on excessive excitation capacity to handle all speed variations, the system uses intelligent control algorithms to anticipate and prevent problematic variations, substituting mechanical oversizing with electronic control intelligence.
Solution Approach 2:
The control apparatus dynamically changes operating parameters including guide vane opening degree, power command values, and effective head measurements to maintain optimal revolving speed. By continuously adjusting these parameters based on real-time conditions, the system prevents excessive speed variations that would otherwise require larger excitation capacity, achieving reliability through parameter optimization rather than hardware oversizing.
Data Source
Figure 1
Figure 2A~2E
Figure 3A~3E
AI summary
A power generation system control apparatus (100) for an adjustable-speed, pumped-storage power plant includes a differentiation circuit section (3001) having a first differentiator (5) and a second differentiator (6) for performing two-step differentiation of a value which is based on a power command value (A). The first and second differentiator (5, 6) perform two-step differentiation of a guide vane opening command value (G) obtained based on the power command value (A). A result value (dG2) of the two-step differentiation is added to the guide vane opening command value (G) to generate a guide vane control command value (H) which is an increased control target value. A true guide vane opening (K) is then subtracted from the guide vane control command value (H) to obtain a guide vane control signal (L) having a larger amount of control.