Electrical solution for gas storage Read more about Electrical solution for gas storage Body Variable-Speed Drive System brings greater flexibility to gas storage Chémery Storage Station, France The challenge Gas consumption in France is irregular through the course of a year, and as such the efficient storage of gas is essential to meet demand. The most economical way to build up safety reserves is to store gas in natural underground reservoirs as an alternative to gas liquefaction. Located 200 km south west of Paris, the Chémery gas storage site is the largest such underground facility in Europe with a capacity of 7 billion m3 serving Paris, Nantes, Lyon, and the South of France. Gaz de France identified two compression groups that required revamping as part of a plan to modernize the Chémery gas station to increase capacity and lower emissions. Both a mechanical drive solution for one compression group (based on a gas turbine) and an electrical solution for the second compression group were selected. In October 2003 GE’s Electrification business was chosen by Gaz de France to supply a Variable-Speed Drive System for the second group, involving a 2-stage compressor which operates in series at 143 bar for gas injection, and in parallel at 85 bar for gas racking, with a gas distribution network at 72 bar. Our solution GE’s electrical solution is based on Variable- Speed Drive System (VSDS) including : • 14.4 MVA transformer • Harmonic filters • Load Commuted Inverter (LCI) SD7000 • Water-cooling units • 10.1 MW synchronous motor 1,700 rpm From the 20 kV power grid, a 14.4 MVA transformer supplies a 10.1 MW synchronous motor through a load commuted inverter SD7000. The 4-pole electric motor running at 1,700 rpm drives the compressor that controls the gas injection and retrieval. With the motor’s range of speed from 65% up to 105%, a gear box raises the speed up to 14,649 rpm. The benefits SD7000 proven technology Electrification’s electrical solution enables continuous operation during the peak summer months, with no halting of equipment . The solution ensures high reliability, no mechanical stress and efficient repairs, to give excellent availability and satisfaction of operation. Our solution is based on the SD7000 Variable-Speed Drive System which enables the speed of a synchronous motor to be smoothly controlled, up to 100 MW. Based on synchronous motor and thyristor technology, it ideally meets all requirements to drive compressors including : • High torque throughout the speed range • Constant torque capability • Good dynamic performance and fast response to load changes Harmonic filters improve power factor Based on extensive experience, Electrification provided suitable harmonic filters for the power grid, to ensure reduced harmonics disturbance, whilst improving the power factor of the whole grid. Power electronics for maximum flexibility At the heart of the SD7000’s control system is the fully digital PEC controller, a very advanced power electronics controller featuring vector control. The PEC controller also uses programmable gate-array logic for maximum flexibility and standardization throughout the product range. In addition, it provides full history recording and status monitoring for quick and simple fault diagnosis. Environment friendly An electrical solution saves energy, thereby reducing associated CO2 emissions and minimizing the impact on the environment , thus meeting stringent requirements related to sustainable development and environmental protection. Meeting compressor requirements • High overall efficiency (> 98.5%) • High availability and reliability • High network disturbance robustness • High starting torque and throughout the speed range • No upper limit of power • Four quadrant operation • Reduced installation time and cost
Full electrical solution for FPSO Read more about Full electrical solution for FPSO Body Variable-Speed Drive Systems (VSDS) for topside and subsea motors - CLOV Offshore, Angola Oilfields The Case A new development pole in Angola CLOV is the fourth development pole in Angola’s deep offshore Block 17, which is operated by Total. Also known as the “Golden Block,” Block 17 covers nearly 4,000 square kilometers, from 150 km to 270 km off the coast . CLOV is a stand-alone development in a four-field cluster consisting of the oilfields Cravo, Lirio, Orquidea and Violeta. These oilfields contain reserves of 505 million barrels of oil at a water depth of 1,050 m to 1,400 m. The first full electrical FPSO GE’s Electrification business was awarded a contract to supply seven complete VSDS, including induction motors, for the main gas compressors and the water injection pumps, as well as two VSDS for subsea multiphase pumps. This project represents the first floating, production, storage and offloading unit to be fully equipped with electric variable-speed drive equipment. The total electrical power is about 50 MW. Feeding subsea equipment The transformers and MV7000 converters installed topside feed the subsea multiphase pump induction motors through 11 km umbilical. Electrification’s advanced converter control allows for driving a motor with a step-up transformer and long step-out distance between the subsea motor and the topside converter. Our solution Four complete VSDS for the high-pressure compressor units, each comprised of : Step-down transformer Medium-voltage MV7000 converter 9.61 MW induction motor 6 kV/1,717 rpm One complete VSDS for low-pressure compressor unit comprised of : Step-down transformer Medium-voltage MV7000 converter 4.89 MW induction motor 6 kV/1,717 rpm Two complete VSDS for water injection pumps, each comprised of : Step-down transformer Medium-voltage MV7000 converter 8.7 MW induction motor 3 kV/1,900 rpm For the subsea multiphase pumps : Step-down and step-up transformers Two medium-voltage MV7000 converters feeding a 2.3 MW induction motor 6 kV/3,797 rpm The challenge Because the project calls for in-depth facilities and production techniques, the customer required high-performing, reliable and efficient systems that would help optimize production in a space-constrained environment. With those key drivers in mind, Electrification designed and provided a compact and lightweight electrical solution based on proven, high-performance technologies for the offshore facility’s pumps and compressors. Feeding topside equipment Transformers and MV7000 converters, which are feeding induction motors, have been installed topside for the high- and low-pressure compressor units and water injection pumps. Their compact design allows for a smaller electrical room. Thanks to the converter 24-pulse topology for network bridge, no harmonic filter is necessary, thus allowing an additional reduction of the equipment footprint and capital expenditures. By using a 6 kV converter, the size and weight of cables between the motor and the converter also are decreased by half. Medium-voltage converters bring high- quality performance With the most compact design available for a medium-voltage converter, Electrification’s high-performance MV7000 solution is based on the latest generation of powerful press-pack IGBT (PPI) technology. The proven Pulse Width Modulation (PWM) three-level inverter provides high-quality performance. Its adjustable PWM patterns and frequency bring a wide range of flexibility for low switching losses, low motor total harmonic distortion, operation at high frequency up to 300 Hz or at long distance, and negligible amplitude of torque pulsation at the motor shaft. The compressors, water injection pumps and subsea pumps for CLOV are powered by the MV7000 converter series. Their water-cooled design, ideal in a space-constrained environment such as offshore applications, allows for reduced investment in room ventilation and air conditioning. In addition, it makes the use of high-capacity diodes and PPI optimal versus footprint . Water-cooling converters also operate with very low noise. Powerful medium-voltage induction motors Our medium-voltage induction motors offer lower weight and inertia advantages as well as lower maintenance costs for applications requiring high reliability. They are available on any type of drive system for most industrial applications, including FPSOs. These machines also offer higher overload capacity and represent a more cost-effective solution compared to equivalent synchronous machines. Induction motors supplied for CLOV provide the following benefits : More complete plant safety with pressurized Expx IIAT3 motor High efficiency with a direct-drive gearless solution Optimized footprint thanks to water-cooled technology Smooth startup with variable-speed drive control Operating expenditure savings with reduced maintenance service In addition to routine tests on each item of the VSDS, the system (including the cooling system) has been tested at rated power (full speed, full load) prior to installation.
Electrical motors used as starter/helper/generator on an LNG plant refrigeration train Read more about Electrical motors used as starter/helper/generator on an LNG plant refrigeration train Body Bonny Island, Nigeria The Case One of the world’s largest LNG complexes The project for Nigeria LNG Ltd based in Bonny Island, Nigeria utilizes the gas reserves of the eastern part of the Niger delta by converting them to liquefied natural gas for export to industrial customers in Europe and Turkey. The plant has seen substantial growth since start up 8 years ago and now has six liquefaction trains in operation. The capacity of each train is 4 million metric tons of LNG per year. In 2002, GE Electrification‘s business was chosen to supply the first two sets of a complete electrical system for the liquefaction of trains 4 and 5. Subsequently in 2004, Electrification was selected again for the electrical set for train 6. Regarding the liquefaction in the LNG supply chain The most economical transportation of natural gas for destinations upwards of 5,000 miles is through liquefaction. The patented liquefaction process reduces the volume by 600 times. Natural gas liquefaction occurs when the gas is cooled to -160°C (-260°F). Several processes are patented. It consists mainly of methane (C1), ethane (C2), propane (C3), butane (C4) and nitrogen (N2). The liquefaction system used at Bonny Island is a conventional process using a Propane Refrigeration (PR) pre-cooling step followed by a Mixed Refrigerant (MR) condensation cycle. Our solution 3 complete electrical systems each comprised of : • Harmonics filters 33 kV • Network transformer 33 kV / 3 kV • Frequency converter SD7000 15.5 MW • Machine transformer 3 kV / 10 kV • 10 kV switchboards • 2 high-speed motors 3,600 rpm – 10 kV - Power 13 MW each • Cooling systems • Energy Management System The challenge The customer’s requirements were very specific, with only two similar installation set-ups in the world. Electrification was able to meet the challenges of optimizing available energy for the customer by using their technical competencies and capabilities. Original concept to reduce the number of equipment For each train, a converter drives two 2-pole turbo synchronous machines of 13 MW each. One machine is dedicated to the 60 MW compressor of the propane cycle, and the other one to the 80 MW compressor of the MR cycle. The two 2-pole turbo synchronous machines are used as : • Starter: to start the gas turbine by accelerating the shaft until the combustion enables the turbine to work alone • Helper: to provide additional power to the gas turbine if required • Generator: to regenerate the excess of power (automatic energy management) Dynamic stability studies Responding to customer demand, Electrification performed time domain studies of the entire system dynamic behavior, including network, gas turbine and compressor shaft-lines. The studies analyzed different occurring events to confirm the stability of the whole process under any possible situations. LCI converters bring high availability and increased reliability Based on thyristor technology for synchronous motors, the SD7000 LCI drive allows speed control up to 100 MW. Electrification’s proven technology and high reliability, for processes requiring high availability, ensures continuous operation 365 days per year. In addition, the four- quadrant operation enables the regeneration of energy to the network with no additional costs. The fully digital controller integrates all the components of an automation controller into a coherent unit: a mechanical structure for industrial environments, powerful CPUs, high-performance operating system, communication networks and industrial inputs/outputs. Combining the thyristors advantages and the last generation of controllers, the SD7000 converter meets the compressor requirements in terms of : • High overall efficiency (> 98.5%) • High availability and reliability • High network disturbance robustness • High starting torque and throughout the speed range • No upper limit of power • Four-quadrant operation • Reduced installation time and cost Power regeneration for increased efficiency During operation thanks to regeneration of excess power, whenever the need is for any loop to reach more or less power, a system balances the need from the power grid to a gas turbine, from a loop to the other one or from a gas turbine to the power grid. So in static mode, as well as in transitory mode, the gas turbine always performs at its optimal operating point. Energy Management System for smooth operation The Electrical Protection and Control Functionality (EPCF) system monitors energy flow and controls the energy requirements of each compressor (PR and MR). It also communicates the energy balance and status of each part of the electrical system through to the gas turbine control system and the plant’s DCS. Harmonic filters also improve power factor Based on extensive experience, Electrification has studied and designed the suitable harmonic filters for the power grid to ensure reduced harmonics disturbance while improving the power factor of the whole grid. 10 kV switchboards: security in all situations Up to nine 10 kV circuit breakers are installed to ensure proper operation and protection of the LNG trains during start up, continuous running and back up. Increase of availability through the interconnection of each train’s supply The power supply for trains 4, 5 and 6 are interconnected. In the event of breakdown, each converter train can function in back up mode for the neighboring train. From the 33 kV network to the 13 MW synchronous motor shaft end, Electrification carried out all the studies, supplied and integrated the different electric components and commissioned the complete electrical system.
Electrical solution with induction motors for LNG - Yemen LNG Project Read more about Electrical solution with induction motors for LNG - Yemen LNG Project Body The Case Yemen began producing oil and gas in 1986 and exporting liquefied natural gas in November 2009. In 2011, production of natural gas reached 340 billion cubic feet and 164.48 thousand barrels per day of petroleum. With a capital expenditure of $4.5 billion, the Yemen LNG project is the largest industrial project in the country. French company Total holds a 39.6 % stake in the project, with the other participants being Hunt at 17.22%, Yemen Gas Company at 16.73%, SK Corporation at 9.55%, Korea Gas Corporation at 6%, Hyundai Corporation at 5.88% and GASSP at 5%. The liquefaction plant operated by Total at the port of Balhaf on the Gulf of Aden is comprised of two liquefaction trains and has a total capacity of 6.7 million metric tons per year. GE’s Electrification business was awarded a contract to supply two sets of complete electrical systems to drive four compressors for the liquefaction trains. Our solution GE provided two complete electrical systems, with each including : • Network transformer 33 kV / 4x1850 V • Frequency converter MV7612 and accessories housed in ATEX containers • Two 2-pole induction motors: 3,600 rpm – 11 MW each • Cooling systems • Automation system for operator monitor and control interface The challenge From the 33 kV network to the 11 MW induction motors shaft end, GE carried out all the studies, supply and integration of the different types of electrical equipment , and was able to reduce the number of items of equipment . For each train, a converter drives two 11 MW induction motors that are directly coupled to the compressor. The 2-pole turbo induction machines are used as a : • Starter, which accelerates the shaft until combustion starts the gas turbine • Helper, to provide additional power to the gas turbine when required (future operation) Induction motors to replace synchronous motors Since the early 1980s frequency converter technology has evolved so that it now applies to electrical motors and acts as direct drives of pumps and compressors. The latest progress in IGBT technology and advanced motor control allows induction motors to provide higher power in medium- voltage, whereas traditionally, synchronous motors are used for driving compressors. The squirrel cage induction motor rotor is a far simpler construction and is inherently more robust than synchronous motors. The rotor conductors are not insulated, and the rotor does not require any rotor excitation circuit. Benefits of VSI technology Voltage Source Inverter (VSI) technology improves the quality and efficiency of the production and offers lower network interferences (low harmonics and high power factor). MV7000 medium-voltage drive technology also offers the benefits of : • Energy enhancement: The PWM active front end enables regeneration of the energy to the network • High efficiency: Up to 99 percent performance • Reliability: With press-pack IGBT technology, fuseless protection and low component count , the MV7000 has a longer life expectancy even under load cycling • Power density: Up to 1.1 MVA/m3 for the complete drive • Redundancy: Secured continuous conduction of the PPI in failure mode • Safety: Case rupture-free and arc ignition-free due to pressed contacts and no wire bonding Additional advantages of this solution, which is based on an induction motor with IGBT inverter, are its reliability and robustness in induction motors, lower maintenance requirements, and compact size.
