CASE STUDY Disturbance event comparing PMU and SE voltage angle difference in ERCOT Prakash Shrestha Operations Engineer Advanced Network Application. PMU and Units Trip Location in ERCOT Grid. State Estimator and Phasor Measurement Unit.
Disturbance event comparing PMU and SE voltage angle difference in ERCOT
Advanced Network Application
The PMU selected for analysis are as:
Use the SE dataSynchrophasor data to improve online stability monitoring
Operations Support Engineering
The high resolution data from PMUs can provide a system-wide voltage magnitude visualization.
The voltage sensitivity is defined as change in voltage magnitude with power flow through a transfer interface. It can provide an early warning of lack of voltage support.
With the load area getting close to voltage collapse point, the voltage declines as power transfer increases, and its rate ∆V/∆P also increases
A example of tracking real-time voltage sensitivity using PMU data
( capability provided by RTDMS), which request PMUs are installed on bus next to transfer interface and also inside load area.
As the angle differences among buses are tracked with high-resolution PMU data, the inter-area oscillation is visible and can be directly monitored.
During an oscillation event, PMU data can capture the dominant mode of oscillations, and its damping and energy.
Frequency Damping energy
Normal SCADA data on a generator during an oscillation event
High resolution PMU data during the same event
For dynamic stability analysis, the model is important to provide accurate results. PMU data can help to tune the existing dynamic model.
System is stable
Simulation results based on original dynamic models
System is unstable
Simulation results after one exciter model tuned