How do you detect and mitigate voltage collapse in power systems?

2 Prevention strategies

To prevent voltage collapse, implement proactive strategies that can enhance the voltage stability margin and avoid operating near the critical point. Load shedding is one such strategy, which involves reducing load demand to balance the power supply and demand. Another technique is reactive power compensation, which involves injecting or absorbing reactive power to maintain or improve the voltage profile. Generator control is yet another strategy, which includes adjusting generator output and voltage setpoints to provide active and reactive power support. All of these strategies require the use of devices such as capacitors, reactors, flexible alternating current transmission systems (FACTS), automatic voltage regulators (AVR), or power system stabilizers (PSS).

3 Detection methods

When detecting voltage collapse, utilize analytical methods that can estimate the voltage stability margin and the critical point. Such methods include PV curves, which are plots of active power versus voltage at a given bus or line. These can show the maximum power transfer capability, the voltage collapse point, and the bifurcation type. QV curves (plots of reactive power versus voltage at a given bus or line) can also be used to show the reactive power demand and supply, and the voltage collapse point. Additionally, a numerical technique known as continuation power flow can trace the PV or QV curves, locating the critical point. It can also calculate the eigenvalues and eigenvectors of the system Jacobian matrix, indicating the direction and magnitude of the voltage instability.

4 Mitigation tools

To mitigate voltage collapse, use software tools such as voltage stability assessment tools (VSATs) and emergency control systems (ECSs). VSATs can perform static or dynamic voltage stability analysis. They can also provide indicators for preventing or mitigating voltage collapse. ECSs can perform online voltage stability monitoring and control with data from sensors, meters, or phasor measurement units (PMUs). They can also execute emergency actions, like load shedding, reactive power compensation, or generator control to avoid or recover from voltage collapse.

5 Best practices

Follow certain best practices that can improve your performance and reliability, when detecting and mitigating voltage collapse in power systems. These include: conducting regular voltage stability studies and contingency analysis, implementing preventive and corrective control measures based on voltage stability criteria and indicators, coordinating the operation of your systems to ensure adequate voltage support and reserve, and enhancing the situational awareness among system operators through advanced technologies.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?