Ensuring Grid Stability: The Indispensable Role of Online Condition Monitoring for Synchronous Condensers in the Renewable Energy Era

Introduction

The global energy landscape is undergoing a profound transformation, with an accelerating shift towards renewable energy sources such as solar and wind power. While this transition is crucial for a sustainable future, it introduces significant challenges to grid stability. Unlike traditional fossil fuel-based power plants, many renewable energy sources are connected to the grid via inverters, which do not inherently provide the system inertia and reactive power support that conventional synchronous generators offer.

This fundamental change in grid dynamics necessitates innovative solutions to maintain stability, voltage control, and frequency regulation. Enter the synchronous condenser – a vital, often overlooked, asset that is experiencing a resurgence in importance.

The Resurgence of Synchronous Condensers

Synchronous condensers are essentially synchronous machines operating without a prime mover, dedicated solely to providing reactive power to the grid. Their ability to rapidly absorb or inject reactive power makes them invaluable for voltage support and power factor correction.

More importantly, synchronous condensers inherently provide system inertia—a key element in mitigating frequency fluctuations caused by sudden changes in generation or load, which are common with intermittent renewable energy sources. As traditional power plants retire, synchronous condensers are stepping up to fill this critical gap, helping maintain grid stability and reliability. Their role is no longer supplementary; it has become foundational in power systems that increasingly depend on non-conventional renewables, as evidenced by recent blackout events worldwide.

300 MVAr Synchronous Condenser in Brazil

The Imperative of Online Condition Monitoring

Given their critical role in grid stability, the continuous and reliable operation of synchronous condensers is paramount. Any unexpected downtime or failure can have cascading effects, potentially leading to widespread grid instability and blackouts.

This is where an advanced online condition monitoring system (CMS) becomes indispensable. Unlike periodic offline inspections, CMS provides real-time insights into the health of these machines, enabling proactive maintenance and preventing catastrophic failures. The dynamic operational demands placed on synchronous condensers, particularly the frequent changes in reactive power and excitation cycles, can induce significant mechanical and electrical stresses. These stresses can lead to subtle defects that, if undetected, can escalate into major issues according to the PF curve below:

FP curve

A Multi-Sensor Approach for Early Detection

An effective CMS system for synchronous condensers integrates multiple sensor technologies to provide a comprehensive diagnostic picture. Key among these are:

•Vibration Monitoring: Sensors strategically placed on bearings detect minute changes in vibration patterns following ISO 20816 standards. These changes can indicate mechanical imbalances, bearing deterioration, shaft misalignment, or even early signs of rotor pole issues caused by thermal cycling from frequent excitation changes. Early detection of these anomalies allows for timely intervention, preventing further damage and costly repairs.

Bearing instrumentation considering relative and absolute vibrations 

•Air Gap Monitoring: Non-contacting sensors continuously measure the air gap between the rotor and stator following ISO 19283 standards. Variations in the air gap can signal rotor and stator eccentricity and stator core deformation. Maintaining a consistent air gap is crucial for efficient and stable operation, and deviations can lead to increased vibrations and potential rubbing.

•Magnetic Flux Monitoring: Magnetic flux sensors provide critical insights into the electrical health of the rotor and stator windings. They are particularly effective at detecting inter-turn shorts in the rotor poles, a common failure mode exacerbated by the frequent excitation changes in synchronous condenser operation. Early detection of these electrical faults is vital, as they can rapidly lead to severe damage if left unaddressed.

Air-gap and Flux monitoring sensors

By combining data from these diverse sensors, an advanced CMS system can identify developing defects in their earliest stages, often before they become visually apparent or cause significant operational disturbances. This multi-sensor approach, coupled with intelligent diagnostic algorithms, transforms maintenance from a reactive to a predictive process, maximizing machine readiness and minimizing unplanned outages.

AQTech's Expertise with Synchronous Condensers in Action

At AQTech, we understand the critical importance of synchronous condensers in the evolving energy landscape. We have successfully implemented and operate advanced online condition monitoring systems for numerous synchronous condensers across various countries, with over 2.000 MVAr being monitored.

Our expertise spans a wide range of machines from leading manufacturers, including GE, Andritz and WEG. Our proven solutions provide real-time insights and automatic diagnostics of failure modes, enabling our clients to optimise the performance, extend the lifespan, and ensure the continuous readiness of their synchronous condenser assets.

Partner with AQTech to ensure the stability and reliability of the grid in the renewable energy future.

Contact us at sales@aqtech.com and learn more.