Containerised diesel generating sets are proving their worth in challenging environments, reports Frank Ponsonby.
When working on a recent project for a customer requiring additional power on one of its oil platforms, a power supply expert encountered a rather considerable challenge that needed to be overcome. The main electrical power supply to the platform is imported over 40km from a third-party operator's facilities through a 33kV subsea cable link. Under certain conditions, this link could be limited to 3MVA; less than sufficient for full production.
To ensure sufficient power was always available to meet the requirements of full production, a key objective was the installation of two new offshore generators, each rated to deliver 2MVA Prime (continuous operation) of additional power.
Dale Power Solutions supplied two containerised automatic start diesel generating sets (model MLE2500), each producing a continuous output of 2,500kVA, 2,000kW, 6,600V at 0.8 power factor.
Prior to dispatch the assembled generating sets were fully tested on resistive load banks. Drawings and documentation were included in accordance with the Supplier Data Requirements List (SDRL) specified by the client.
The engineered package
Paul Roberts, Dale Power Solutions' senior application engineer on this project, comments: "For this application, the generating set we selected was a V20 1,800rpm diesel engine with a prime power rating of 2740kW for generator applications with variable load. Electronic engine speed governing is included to meet Class A1 performance. Engine over-speed protection and emergency shutdown features are enabled by the installation of air intake shut-off valves on the set. Centrifugal lube oil filtration and duplex fuel filters are included for maintainability and reliability."
Automatic and manual start/stop control, synchronising and load sharing is handled by Dale's fully configurable generator set control system. A local generator touchscreen control switchgear panel is housed within the acoustic enclosure and a remote control panel is provided in the client's switch room.
The ISO-style enclosure container has certified lifting lugs and is finished in a painting specification suitable for marine/offshore environments. It is designed with acoustic lining and attenuators in the cooling air inlets and outlets.
Rated performance in the ambient conditions of up to 45°C is achieved with the horizontally roof-mounted, electric motor-driven air-blast radiator. Airflow is managed with four redundant inverter-controlled fans fitted to the inlet plenum and designed to achieve twice the necessary combined airflow for cooling and combustion.
The roof-mounted radiator allows the basic external dimensions to be kept down to 13.5m x 2.44m while still allowing room for the roof-mounted nominal four-hour daily service fuel tank of 2,120 litres and the integrated fire and gas system.
Roof-mounted exhaust gas silencers with integral spark arrestors were produced from 304 stainless steel for durability in the offshore environment.
The enclosure's fire and gas control panel with combined sounder beacons monitors the multiple UV flame detectors and flammable gas detectors installed on the container. The control panel performs weighted monitoring to reduce false alarms. Detected flammable gas trips the motorised gastight dampers fitted to inlet and outlet apertures and shuts down the engine with the air intake shut-off valves.l
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Frank Ponsonby is business development manager, Oil & Gas, at Dale Power Solutions, Scarborough, North Yorkshire, UK. www.dalepowersolutions.com.