Power System Stabilizer for Island Grid Frequency Control
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Solution Overview
Problem
In small-scale independent power supply systems, such as those in isolated islands, it is challenging to determine appropriate time constants for stabilizing power frequencies due to varying operating conditions of power generators, leading to insufficient or excessive control by storage batteries, and potential oscillation phenomena.
Innovation Solution
A power system stabilizer issues control commands to storage batteries based on a rate-of-change limit value calculated from operation information and an interconnection point power flow value, limiting changes in overall power generator outputs to stabilize power frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If storage battery control is used to stabilize power frequency, then frequency stability is improved, but oscillation phenomena may occur due to excessive control
Solution Approach 1:
The invention dynamically changes the control parameter (rate-of-change limit value) based on the total rated output of operating power generators. By adjusting this parameter according to system conditions, the control gain is optimized to prevent oscillation while maintaining frequency stability. The parameter determination unit calculates the appropriate limit value based on real-time generator operation data, ensuring reliable stabilization without excessive control actions.
2Ease of operation
If fixed time constants are used for storage battery control, then control simplicity is improved, but adaptability to varying operating conditions deteriorates
Solution Approach 1:
The invention transitions from fixed time constants to dynamic parameter adjustment. The parameter determination unit continuously updates the rate-of-change limit value based on the total rated output of operating power generators. This dynamic approach allows the control system to adapt to varying operating conditions (such as different numbers of generators online) while maintaining reasonable operational simplicity through automated calculation.
3Speed
If power generator output changes are allowed to follow demand fluctuations, then responsiveness to demand is improved, but power frequency deviation worsens
Solution Approach 1:
The invention applies preliminary anti-action by pre-calculating and limiting the rate of change of power generator output based on system conditions. The parameter determination unit establishes a rate-of-change limit value that prevents excessive frequency deviation before it occurs. By controlling the speed of output changes in advance, the system maintains frequency stability while still responding to demand fluctuations, avoiding the need for reactive frequency correction.
Data Source
AI summary
A technique with which a change in power frequency can be suppressed. A power system stabilizer issues a control command to a first storage battery among a plurality of first power generators and the first storage battery that are connected to an isolated island system via a first tie-line. The power system stabilizer includes a parameter determination unit and a control block unit. The parameter determination unit obtains, on the basis of operation information, a rate-of-change limit value that indicates a limit to be imposed on a total value of changes in the overall output of first power generators in operation. The control block unit generates a command value to be given to the first storage battery on the basis of an interconnection point power flow value measured on the first tie-line and the rate-of-change limit value obtained by the parameter determination unit.