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Ormen Lange, which translated means “Long Snake”, is located 120km off the northwest coast of Norway at a water depth of 800 – 1100 metres.

It is Norway’s second largest gas field with estimated gas reserves of 395 billion cubic meters, and an annual production of 20 billion cubic metres. Gas production from the Ormen Lange Field on the Norwegian continental shelf started on 13th September 2007.

Powering the world’s second-longest sub-sea gas pipeline

At the heart of this historic project, to deliver gas via the 1200km “Langeled” sub sea gas pipeline, the second longest in the world, from Nyhamna in Norway to Easington on the UK east coast, are four 48MW export gas compressors driven by BRUSH MAX 2-pole synchronous motors.

Operating at speeds between 2,520 rpm and 3,780 rpm, these closed circuit air to water (CACW) cooled MAX motors are a derivative of the very successful BRUSH DAX range of turbogenerators.

The motors are configured for variable speed operation powered by a load commutated inverter (LCI).

“The units are working to plan with no issues, a real credit to BRUSH engineering and build”
Project Manager, Ormen Lange

As part of the customer’s rigorous testing programme for these machines, certified for hazardous area operation, the motors were required to perform a 48MW full load, full speed, back to back test with the project drive equipment. In addition, a variable speed, full load string test was carried out with the contract compressor equipment.

The project, seen as one of the industry’s most successful development programmes, delivered on time and on budget. Today the facility is operated by Norske Shell and delivers over 20% of the UK’s gas.

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Geothermal power production is a form of renewable energy generation that harnesses thermal energy from underground sources.

Boreholes are drilled into the geothermal source and water is injected at pressure to be heated. The water returns in the form of steam, which is used to drive geothermal steam turbines. The driver in turn, rotates a generator which produces electrical power.

The thermal energy must be of a certain temperature to be suitable for power generation, and the location of the energy sources meeting this requirement are often in environmentally challenging locations.

The Challenge

BRUSH was asked to provide generators for a location in Chile specially adapted for extreme conditions. The location of the site was at high altitude in the Atacama Desert at 4,500m. At these altitudes the air is much thinner and had high levels of hydrogen sulphide (H2S) and sulphur dioxide (SO2) gases. We called on our long experience in designing engineered solutions for generator applications to meet this challenge.

The Solution

Ensuring the equipment used to produce the power could endure harsh elements was imperative, so we supplied two specially modified, 27.6MW, four-pole, 1,500r/min generators with a rated voltage of 9,500V and a power output of 32.5MVA. Each of the dual-shaft generators were powered by two 15MW turbines and designed to withstand the challenges presented by extracting geothermal energy in 4,500m conditions.

At high altitudes the air is much thinner which can increase the potential for damaging partial discharge activity in the stator winding.

Our design team developed a solution that de-rated the generation voltage to reduce the risk of stator damage, while maintaining the specified power output. This means that the generators will be kept online by optimising the stress on the electrical insulation system

We evaluated solutions for generator cooling due to the thinner air, this was complicated by both the ambient temperatures at extremes lows of -31°C, and the presence of toxic H₂S and SO₂ gases.

To counter these threats, we designed a pressurisation system that provided clean air to the inner part of the generators and that featured a special filtration system to neutralise the H₂S and SO₂ gases. Specialized heating was installed to keep the generator warm during times when the system was idle.

This application location also presented human challenges. Service personnel could only be present at such extreme altitudes for short periods of time without suffering from altitude sickness. This meant installation, and later maintenance, had to be carefully planned and scheduled with the operator. Strict guidelines were put in place to ensure the safety and health of the team.

The Result

We completed the design and build within the agreed delivery lead time, and power output specification. In doing so, we contributed to the first power plant built at this altitude worldwide, increasing the number of locations that can be considered for geothermal energy production.

When you have a challenging power generation application contact BRUSH to discuss our solutions.

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Guangzhou Metro is the metro system of the city of Guangzhou in Guangdong Province of China. It was the fourth metro system to be built in mainland China, after those of Beijing, Tianjin and Shanghai.

Having delivered 2.054 billion rides in 2013, Guangzhou Metro is the sixth busiest metro system in the world, after the metro systems of Tokyo, Seoul, Moscow, Beijing, and Shanghai and operates 164 stations.

The city, in the south of one of the world’s most populous countries, was initially planned to have a two-line metro system, which uses some of the latest light-rail technology, and was a model for a completely integrated project.

The number of lines was, however, increased later. The metro now operates eight lines, with an additional six lines underway.