Retrofitting pitch backup systems with ultracapacitors for less maintenance, more uptime
Every hour that a wind turbine is offline is an hour of lost revenue. Wind farm operators must look for every way they can minimize downtime. The battery backup power for a turbine’s emergency pitch control system can pose several problems for site personnel, including regular maintenance, failures and turbine downtime to address issues.
That’s why in 1999 FREQCON designed one of the first ultracapacitor pitch systems for large wind turbine OEMs, and shortly thereafter became the original inventor and manufacturer of the first retrofit solution for existing wind turbines.
By identifying an energy storage solution that surpasses batteries in performance, reliability, safety, and lifetime, FREQCON has been able to help leading wind turbine OEMs and wind asset managers significantly reduce pitch system maintenance efforts and increase uptime.
The traditional battery-based pitch backup system
Without proper maintenance and care, batteries can present a variety of reliability problems for wind farm personnel. Batteries may fail for a number of reasons: factors such as extreme hot or cold operating temperature conditions can cause an increase in batteries’ internal resistance, which contributes to aging, batteries lose power over time due to self-discharge, and improper warehouse storage can cause a failure after the battery is installed in the pitch system.
Because of these challenges, batteries often require regular maintenance and replacement. Technicians must engage in a lengthy process to shut down a turbine and climb to the hub where they can switch out failed batteries with new ones. This is a time-consuming process than robs a wind farm of revenue hours.
FREQCON identified the common problems associated with batteries and how these problems ultimately affect the overall operation of the pitch system and the turbine. Considering that the turbine hub is a difficult-to-access location for battery maintenance efforts, FREQCON innovated a pitch backup system based on significantly more reliable ultracapacitor technology.
Unlike batteries, ultracapacitors are electrostatic energy storage devices that do not rely on an internal chemical reaction to deliver power. This makes ultracapacitors much more durable in the face of extreme hot or cold temperature conditions (from -40 to 65°C) and capable of quick charge and discharge.
Over the past 20 years, wind farms across the globe have partnered with FREQCON to leverage the advantages of ultracapacitors for pitch control. FREQCON’s drop-in solution fits seamlessly into the wind turbine’s existing emergency power unit for straightforward installation and operation. The ultracapacitors help shut down the turbine by pitching the blades to zero in the case of a grid failure or high winds.
In addition to providing fast, reliable power for pitching the blades, the ultracapacitor-based retrofit eliminates battery faults, which site personnel report as time-consuming in terms of troubleshooting. Since ultracapacitors have much longer life than batteries, they eliminate the need for technicians to make regular climbs to replace the pitch system’s backup power, which in turn contributes to greater technician safety.
Retrofitting backup systems for optimal pitch control performance
The wind doesn’t always blow reliably. When it does, wind farm personnel want to ensure that their turbines are in working condition to catch those revenue-generating hours. The turbine’s emergency pitch control is a critical system that requires reliable backup power but can cause turbine downtime due to battery maintenance.
Since FREQCON introduced the ultracapacitor-based pitch backup system, leading wind turbine OEMs, including multinational wind turbine manufacturer Goldwind, have installed more than 20,000 wind turbines using FREQCON’s pitch technology. In addition, today nearly 1,000 fielded turbines have been retrofitted by wind farm operators. FREQCON’s ultracapacitor retrofit is designed to outlast the 20-year lifetime of newly installed turbines, providing unmatched pitch backup system reliability. FREQCON’s full spectrum of capabilities includes in-house R&D, software and hardware development, and in-house quality testing. Backed by a global install base, qualified ultracapacitor suppliers, and more than 20 years of experience designing, building and licensing its pitch technology to top turbine manufacturers, FREQCON is dedicated to helping wind farms streamline operations and minimize OPEX with its retrofit solutions.
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