Generator Shedding Correlation Line Estimation Using Stability Limits
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Solution Overview
Problem
Conventional methods for estimating generator shedding information in power grids face significant accuracy degradation due to local concentration of sample points, leading to potential shortages in generator shedding amounts when only one representative point is calculated for each section, resulting in unstable correlation line estimation.
Innovation Solution
A system stabilizing controller that collects grid information, calculates generator shedding amounts, and estimates a correlation line using a stability limit point and generator phase angle curve to determine suitable generator shedding amounts, ensuring accurate estimation even with locally concentrated data points by incorporating a backup calculation unit for stability limit power flow and shedding amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a correlation line is estimated using conventional least-squares method with locally concentrated sample points, then the calculation process can be completed, but the estimation accuracy of the correlation line is significantly degraded
Solution Approach 1:
The patent applies preliminary action by pre-calculating stability limit information (stability limit power flow amount and stability limit generator shedding amount) before actual generator shedding is needed. This is done by performing stability limit calculations in advance using the generator phase angle curve, acceleration energy, and deceleration energy, so that when sample points are locally concentrated and conventional estimation fails, the pre-calculated stability limit data can be used to ensure accurate correlation line estimation.
Solution Approach 2:
The patent introduces stability limit information as an intermediary element between the power flow amount and generator shedding amount. By calculating the stability limit power flow amount and stability limit generator shedding amount as intermediate reference points, the system can accurately determine the correlation line even when conventional methods fail due to locally concentrated sample points, thus improving both accuracy and reliability.
2Productivity
If only one representative point is calculated for each section due to local concentration of sample points, then the calculation can proceed, but the correlation line estimation becomes unstable and inaccurate
Solution Approach 1:
The system performs preliminary calculation of stability limit information in advance, storing the stability limit power flow amount and stability limit generator shedding amount. This pre-calculated data serves as a reliable reference that can be used when sample points are locally concentrated, ensuring both calculation efficiency and estimation accuracy without requiring multiple representative points from concentrated data.
Solution Approach 2:
The patent changes the approach from relying on multiple sample points to using stability limit parameters (acceleration energy, deceleration energy, generator phase angle curve) as the basis for estimation. By transforming the estimation basis from empirical sample points to physically meaningful stability limit parameters, the system maintains high accuracy even with limited sample points.
3Ease of operation
If the slope of the correlation line is fixed at a setting value with only one representative point, then the correlation line can be determined, but the estimation accuracy is significantly degraded
Solution Approach 1:
The patent introduces stability limit information as an intermediary that provides physically meaningful reference points for determining the correlation line. Instead of fixing the slope at an arbitrary setting value or relying on insufficient representative points, the system uses the stability limit power flow amount and stability limit generator shedding amount as mediating references that ensure both determinability and accuracy of the correlation line.
Solution Approach 2:
The system changes from using fixed setting values or limited representative points to using stability limit parameters derived from acceleration energy, deceleration energy, and generator phase angle curve. This parameter transformation ensures that the correlation line determination is both simple (using pre-calculated stability limits) and accurate (based on physically meaningful stability criteria).
Data Source
AI summary
A system stabilizing controller for estimating and controlling stability of a power grid includes a collection unit collecting grid information including a power flow amount from the power grid and a calculation unit calculating a generator shedding amount at a fault observation point on the basis of the grid information and estimating a correlation line on the basis of the power flow amount and generator shedding amount. The calculation unit determines a generator phase angle curve that is the relationship between the internal generator phase angle of a generator connected to the power grid and the power flow amount, determines a stability limit power flow amount on the basis of the amounts of generator acceleration energy and deceleration energy in the generator phase angle curve, determines a stability limit generator shedding amount corresponding to the stability limit power flow amount, and estimates a correlation line including a stability limit point.