For many years, gas turbines generating renewable energy have been started by hydraulic or even high flow air systems. Hydraulic technology is the current prevalent method in traditional gas turbine starter applications; the seemingly more flexible and modern electrical alternatives simply could not meet the power generation demands of the application. Today, however, new technological advances have turned electrical solutions into a superior alternative to hydraulics.
The early benefits of hydraulics established it as the sole suitable solution to starting gas turbines: compact, lightweight and mounted directly on the gas turbine frame itself. Still, they suffered from the well-known weaknesses of most industrial oil controlled systems; higher maintenance costs, leakage, fire risks and increased insurance costs associated with their use in explosive power generation environments. New trends are also highlighting another limitation of older style starters; gas turbines are increasingly used to support renewable energy plants so must be started more frequently than before; because of the increasing cost of energy, gas turbines are operated only when needed and stopped when not required. Also In cold ambient temperatures, hydraulic starters need a longer start-up time due to the requirement to allow oil to heat before they can be successfully operated, this means they don’t offer the same flexibility as electric when operating in this new environment.
Electromechanical technology addresses limitations
The latest electromechanical technology addresses limitations of hydraulic starters and now they:
- can be instantly operated to meet demand or stopped to save energy;
- don’t use any combustible oil reducing insurance costs;
- are low maintenance.
Still, until recently electrical starters couldn’t be considered a viable alternative to hydraulics, why? Size and weight: using industrial induction motors, an electric starter is around 3 times bigger and much heavier than existing hydraulic starters, thus preventing the drop-in replacement without a prohibitively costly turbine redesign.
So what has changed?
Our engineers developed a new electrical starter system that is customized to meet the demands and duty requirements of gas turbine packages. Across our nine core technology disciplines, our engineers collaborated to understand and address the challenges of the application making it possible to introduce electromechanical technology for both existing fielded fleets and new gas turbine production.
A light-weight ATEX/IECex certified permanent magnet motor with compact footprint allowing it to replace existing hydraulic starters without major machine redesign, coupled with a modular electrical drive sized to the exact power requirements of the application and meeting tight space constraints.
Power Generation Europe presentation
This solution was presented by Adrien Tenga, marketing manager, Parker SSD Drives Division in Europe, at the 2013 Power Generation Europe conference and exhibition in Vienna Austria. The premise of the talk was that electric motor technology can be used to replace new and existing hydraulic and pneumatic starter systems, reducing the need for hydraulic and pneumatic infrastructure.
It addresses the oil leakage and mist hazards which has set a wider industry trend away from using high-pressure oil for the following reasons:
- Pollution: Oil leakage and mist are environmental pollutants
- Insurance Cost: Oil leaks are a fire hazard and can increase the cost of insurance
- Health & Safety: Oil mist can reduce lung capacity, cause respiratory disease, and reduce overall worker productivity
- Disposal: New European proposals for waste oil, added under the European Liability Directive (ELD) “Environmental Damage protection” regulations, are increasing oil disposal costs
- Legislation: Oil mist safety is managed in ISO14001
Today: Electric starter
- Motor weight < 70kg
- Motor torque < 700Nm
- Motor max power < 300kW
- Motor speed <7000rpm
- ATEX/IECex certification
Tomorrow: Even less hydraulics
- Inlet guide vane actuators,
- Fuel control valves
- Bypass air valves
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