Paper title: OFFSHORE PLATFORM POWERED WITH NEW ELECTRICAL MOTOR DRIVE SYSTEM

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1 Paper title: OFFSHORE PLATFORM POWERED WITH NEW ELECTRICAL MOTOR DRIVE SYSTEM Copyright 2005 IEEE. Published at: Fifty-Second Annual Technical Conference of the Petroleum and Chemical Industry Committee Denver, CO, USA, September 12-14, This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of ABB Power Technologies AB s products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.

2 OFFSHORE PLATFORM POWERED WITH NEW ELECTRICAL MOTOR DRIVE SYSTEM Copyright Material IEEE Paper No. PCIC Jan O. Lamell, M.Sc E.E. Timothy Trumbo, B.Sc Tom F. Nestli, M.Sc, Dr. ing. Member, IEEE Senior Member, IEEE ABB Automation Technologies ABB Inc. ABB AS Drives, Motors & Power Electrical Machines Automation Technologies Electronics Divisions Elmotorgatan Livingstone Avenue PO Box 6540 Rodelokka SE Västerås North Brunswick, NJ NO-0501 Oslo Sweden USA Norway Abstract - A new type of compressor motor drive and electrical transmission system will be installed on a Norwegian offshore platform in the North Sea. New compressors are required to compensate the declining reservoir pressure and boost the gas capacity through the pipelines to mainland. The variable speed drive systems consist of two 56 kilovolts, 40 MW synchronous cable wound motors and two directly connected high voltage direct current transmission lines, which are powered from mainland. The electrical drive system will increase and secure the gas production at a higher efficiency than conventional gas turbine driven compressor systems and avoid emissions of environmentally harmful substances from the platform. The equipment in the electrical drive systems were under test during 2003 and are delivered for assembly on the mainland, after which it will be shipped out to the platform. The drive systems are scheduled for installation in 2004 and commissioning in The application of a variable speed drive on a platform powered from mainland and utilization of a new combination of electrical cable wound motor and high voltage source converter, have required accurate analysis and design and thorough testing of the motor. Index Terms High-voltage motor, Compressor motor, offshore platform, electrical drive, variable speed, variable frequency, HVDC transmission. Therefore, until now, almost all power on offshore installations has been generated locally by gas turbines or diesels with low efficiency (often as low as 20 %-25 % during the best conditions) and high greenhouse gas emissions as a result. Platforms on the Norwegian shelf contribute 25% of the nation's overall carbon dioxide (CO 2 ) emissions. If the electrical energy could be taken from land, more efficient and less polluting energy production could be used. I. INTRODUCTION The power demand on an offshore installation - such as an oil or gas platform - is substantial. Depending on the requirements of the process and equipment on the installation, the required power may be in the range of a few up to several hundreds of megawatts. In the rare cases where installations are located close to shore, electrical power can be transmitted from shore using AC cables. However, AC power supply becomes impractical for long distances, i.e. more than km (31-62 miles) and/or high power. The use of conventional, line commutated High Voltage Direct Current (HVDC) transmission systems has also been considered. However, the size and weight of the HVDC station with its filter and synchronous condenser has, together with the complexity of control (particularly during start-up), prohibited its use on offshore installations. Fig. 1 Two HVDC converter station offshore modules The Kyoto Protocol supports trading of greenhouse gas emission, so CO 2 emissions can therefore represent a cost. On the Norwegian Continental Shelf, CO 2 taxation already in effect makes emissions costly even without such trading. If electrical power can be supplied from shore - for power supply as well as compressor drivers - CO 2 emissions from offshore installations are eliminated. This leads to a significant cost saving for oil companies. In addition, transmission of electrical energy from shore involves less maintenance, longer lifetime and higher availability than gas turbines and diesel engines. If the transmission equipment can be located on decommissioned installations offshore, the postponed removal cost for the installation can be an important factor as well.

3 In addition, the environment can undoubtedly be saved from considerable amounts of greenhouse gas emissions if the electrical energy can be produced onshore instead of in lowefficiency power stations offshore. A land based Combined Cycle gas power plant from which waste heat is utilized can have efficiency in the range of 75-80%. Even with up to 10% losses in a long electrical power transmission to an offshore installation, the saving will be significant for most installations. the use of gas turbine driven compressors, would result in annual emissions of tonnes ( lbs) of CO 2 and 230 tonnes ( lbs) of NOx. Avoidance of such emissions, by using electrical drive systems powered from shore, is a relief for the environment and, with the CO 2 taxation in effect, a significant reduction of operating costs. II. ELECTRICAL TRANSMISSION AND DRIVE SYSTEM MW AC Power Fig. 2 Conventional compressor drive compared with electrical power transmission from land to platform Replacing local generation on offshore installations with electric power supply from shore is advantageous for two important reasons: It may be economically interesting as well as environmentally friendly, leading to reduced greenhouse gas emissions [1]. On a Norwegian gas platform, the reservoir gas pressure declines as a result of depletion of gas from the reservoir, making it necessary to install compression equipment in order to maintain, and increase, the gas production capacity. The compressors will allow more gas to be pushed through the pipelines, which will increase the production capacity of the platform. Conventional gas compression systems offshore use gas turbine driven compressors. It is estimated that for this project 132 kv Switchboard DC Power Gas turbine Move if CO2 tax is reduced km miles Onshore Rectifier Station Subsea Cable A conventional gas turbine driven compressor can be compared to a fixed speed electrical motor drive, because the gas turbine has a limited speed range. Variable speed drive (VSD) systems have advantages compared to fixed speed. The motor speed and power can be controlled to match the compressor load with a minimum of power consumption. The soft starting of the motor reduces the motor and shaft system stresses and increases the motor lifetime. During winter, the required gas production peaks while summer demand is often lower. Still, the gas platform in question is swing producer for other gas platforms, so that required production may vary quite frequently. Variable compressor speed is therefore a requirement. Conventional VSDs at this power level are mostly based on Load Commutated Inverters (LCI) feeding synchronous motors. However, in this particular installation on an offshore platform distant from main land and space and weight are restricted. The following considerations led to the chosen design: Required shaft power is 2 times 40 MW ( HP) and the platform is located 70 km (43.5 miles) from shore. Hence, AC power transmission is not a viable alternative high voltage DC is required. Conventional HVDC requires communication between rectifier and inverter for control purposes. For VSD operation, conventional HVDC is not well suited due to complexity of control during start-up. Voltage Source Converter (VSC) based HVDC was therefore chosen. If the voltage levels of the HVDC transmission and motor can be matched, the bulky, heavy transformer between the two can be avoided. Cable wound synchronous motor was therefore chosen. The HVDC transmission and variable speed drive system is illustrated in Figure 3. VSC for HVDC transmission was first put in operation in Since then, six land-based transmissions have been commissioned. Offshore Inverter Station VSD HV Motor Precompressor 70 km 40 MW 56 kv MS Gear Fig. 3 HVDC Transmission and variable speed drive system

4 VSC for HVDC transmission has been achieved by series connection of Insulated Gate Bipolar Transistors (IGBT), bringing the advantages that have made VSC successful in industrial drive systems to HVDC transmissions. IGBTs, with their current control and turn-off capabilities, enable application of Pulse Width Modulation (PWM) for generation of the fundamental voltage. Figure 4 shows the principle of PWM. +Ud -Ud +Ud Usw Uac III. MOTOR CONTROL The state of the art control of a synchronous motor for VSD connected to a VSC using PWM is to use a rotor position indicator. With information of the amplitude of the stator and rotor current and the rotor position, vector control can be used. With fast vector control the active and reactive power can be controlled independently and the current and voltage harmonics can be kept at a low level. The inverter control software is adapted for both motor speed and torque control. The motor currents and voltages and the rotor position are measured and used together with an advanced model of the machine's electromagnetic parameters to calculate the converter switching pulses in much the same way as for smaller industrial variable-speed drives. Unity power factor and low harmonics are assured, along with a sufficiently high dynamic response, over the motor's entire operation range. There is no need for communication between the rectifying control system on land and the motor control system on the platform; the only quantity that can be detected at each end of the transmission system is the direct current (DC) link voltage. As the DC link cannot store much energy, the motor control system is design to follow even rapid changes in power flow at the opposite end without disturbing motor operation. -Ud IV. CABLE WOUND HIGH VOLTAGE MACHINE Fig. 4 Principle of pulse width modulation The control capabilities enable fast and independent control of active and reactive power in power transmission applications, or torque and magnetization in drive applications. With an output voltage of 56 kv from the inverter, only innovative motor technology could help achieve the goal of a transformer-less drive system: A cable wound high voltage motor, which will be described below. The chosen system is novel in several aspects: It will be the world s first VSC based HVDC transmission offshore; It will be the world s first cable wound high voltage motor offshore; and It will be the world s first electrical drive system that operates at 56 kv AC without transformer between inverter and motor, and with the rectifier located 70 km from the inverter. The control system has been tested with laboratory scale set up consisting the HVDC control system and a small DC transmission link. A small (100 kw, 134 HP) synchronous motor was used equipped with rotor position indicator and excitation system emulated to ensure that the interface to the control system was identical to the actual system. This test was done to verify that the HVDC transmission system control could be used for the motor drive system and furthermore the control modifications needed for the adaptation were identified. With this test system it was possible to verify: Normal start / stop. Load and reference variations. Encoder and excitation malfunction. AC system disturbances, i.e. ride through. The machine models used in the digital simulations. Operator training and demonstrations. The launch of an innovative cable technology in 1998 raised the prospect of increasing motor voltage ratings to radically higher levels. The innovation was the use of High Voltage (HV) cables as the windings of electrical machines [2]. The HV cable-winding concept was first applied to an electric generator [3]. A number of these generators have already entered service, with voltage levels from around 30 kv up to 155 kv. The concept has also been applied to motors; with the development of a synchronous cable wound motor using a conventional solid salient pole type rotor. It is currently being offered for voltages up to 70 kv. The new design can also be used for electric generator applications. The first motor was installed in November 2001 [4] driving a compressor in an air separation plant (see figure 5). Fig. 5 First High-Voltage motor installation

5 The motor is rated 42 kv and 9 MVA. It is also used for supporting the electrical network with reactive power and boosting during the starting of other large motors in the area. The motor has been running since 2001 without any problems. V. MOTOR DESIGN Important design conditions for an offshore installation are area classification, environmental conditions, weight, space and dynamical requirements in addition to the operational requirements. The motors will be installed in a hazardous area classified as Zone 2, Gas group IIA and temperature class T3, corrosive and saliferous atmosphere. Since the installation is on an existing platform the allowed weight and space were limited. As normal for an offshore installation the compressor, gearbox and motor train are placed on a combined skid, which means high demands on the mechanical dynamic design due to the weak foundation. In addition the requirements from the variable speed drive system have to be met. The motors can be running continuously at a speed in the range from 1260 to 1890 rpm (42 to 63 Hz). The shaft power, the line-to-line voltage and the stator current limits are shown in figure 6. Shaft power [MW] and Line-to-line voltage [kv] Shaft power Line-to-line voltage Stator current Frequency [Hz] Stator current [A] Fig. 6 Operation limits for High-voltage motor in respect of shaft power, line-to-line voltage and motor stator current During the design process the following objectives had to be considered: Suitable Ex design Converter output voltage, current and frequency Cooling system Machine layout Stator and cable design Rotor and excitation system Mechanical dynamics, e.g. critical speed and bearing design A. EX design Because of the hazardous area classification for the motor, Zone 2, Gas group IIA and temperature class T3 (requires that all parts of the machine have a maximum surface temperature of 200 C (392 F)), common requirement on offshore installations, is the Motor a pressurized EEX (p) design with increased safety according to EN [5]. Even if the motor is located in a Zone 2 area the motor is required to be according to Zone 1. Zone 1 requires the motor to be designed for the temperature class, here T3, both inside and outside the machine cover during start-up and continuous operation. The reason is that in case of failure of the pressurization system the machine should be stopped immediately and if any surface has a higher temperature than 200 C (392 F), it is imperative that the pressurizing system secures that no gas can enter the motor until the temperature is below the specified temperature class. For a Zone 2 motor a simplified pressurization could be used without considering the surface temperature inside the motor. B. Converter output For variable speed drive operation, it is important to define the level of voltage and current harmonics and the voltage dv/dt, caused by the converter or the combination of a converter and a motor. The current harmonics increases the losses in the stator winding and rotor pole iron. The current harmonics levels for the VSC using PWM and harmonic filters have shown to be lower than for conventional LCI drive system, therefore there will be no significant increase in stator winding losses. For analysis of the cable winding with respect of transient voltage phenomenon caused by the VSC (VSC switching frequency is in the order of 2000 Hz and rise time 6 µs, see figure 7), it was necessary to build a high frequency model of the motor. +60 kv -60 kv Rise time 6 µs Fig. 7 The rise time for the square shaped voltage from VSC is approximately 6 µs from 60 to +60 kv The model allows possible critical issues in the cable winding to be analyzed, e.g. the transient peak (figure 8) and the root mean square (r.m.s.) voltage in the insulation screen. This information is used when designing the stator winding grounding system.

6 Fig. 8 Voltage transients who can occur on the insulation screen of the cable for a VSC fed motor C. Cooling system and machine layout To minimize the motor weight an efficient cooling system is needed. Since cold seawater is available at most offshore installations it is the natural choice for the motor cooling. To make the cooling system more efficient, it is divided into two circuits, one for a direct cooling of the stator and one for conventional water-air heat exchanger. The latter water-air cooler is necessary for the rotor cooling system. The direct cooling system consists of fresh water-cooled stainless steel pipes. The same water is also used for cooling the HVDC equipment. The fresh water itself is cooled by seawater. The water-air cooler elements use seawater as cooling medium and are made of titanium to ensure long lifetime. Fan Water-Air heat exchanger Stator Rotor Fan Exciter Stator cooling Fig. 9 Schematic drawing showing the High-Voltage motor water-air and direct water cooling system The motor has as mentioned earlier an operation window from 70 to 105% of rated speed and full torque between 80 to 100% speed, therefore it is an advantage to use separate fans to force the inner cooling airflow. As a result the airflow will be almost independent of the rotational speed of the main rotor. polyethylene (XLPE) insulated cable is used as stator winding. A semi-conducting insulation screen (IS) on the outside of the cable insulation ensures safe connection to the stator core. In order to reduce eddy current caused by the stator winding's fundamental current and the current harmonics, caused by the drive system, varnish insulated copper strands are used. The cable used for the VSD motor is designed for U 0 = 34.6 kv (correspond to a line-to-line voltage of 60 kv). The XLPE insulation system is classified for an electric field strength (EF) of 10 kv/mm (254 kv/in) for the conductor screen (CS) and 5 kv/mm (127 kv/in) for the IS. The cable has been type tested for the level U 0, which corresponds to an EF of 7.4 kv/mm (188 kv/in) for the CS and 4.8 kv/mm (122 kv/in) for the IS. Approximately 3.4 kilometers (2.1 miles) cable was used for one motor. This gives 1.14 kilometers (0.7 miles) cable per phase. Every phase was wounded in one continuous cable without joints. E. Mechanical dynamic design The speed range in combination with weak foundation (skid) set high demands for the mechanical dynamic design of the motor and skid. The interaction of the motor dynamics (rotor, bearings, base-frame, exciter and stator) and skid dynamics has been analyzed in order to develop a suitable complete dynamic system with low vibration levels. The motor is designed with minimized rotor bearing distance in order to increase the first bending mode of the rotor as much as possible. The first rotor-bending mode is calculated to be about 2500 rpm at factory test stand (separation margin 32% above highest operation speed 1890 rpm) and about 2350 rpm at the skid on the platform (separation margin 24 %). Several types of bearing solutions were investigated, e.g. cylindrical, 2-lobe (lemon bearing) and 4-lobe bearing designs. The most suitable and the final choice was the 2-lobe bearing type. A finite element model (FE-model) of the motor was created early in the design phase of the project and has continuously been calibrated to the results from the experimental modal analysis. The analysis has been done for the following parts: Welded stator (without winding) Wounded stator (include winding) Winding end Exciter (stator) Rotor Cooler top Motor hanged up, without cooler top Motor standing at factory test stand, without cooler top Complete motor, standing at factory test stand The motor FE-model (figure 10) was used in the Motor design developing process and as the motor-part in the complete system FE-model (incl. skid, motor, gearbox, compressor and enclosure) for the complete system dynamic analysis. D. Stator and cable design The know-how achieved from the first high-voltage cable wound motor was of a great value when designing the VSD motor, e.g. same type of slot has been used. A cross-linked

7 brush less exciter with AC windings on both stator and rotor. The alternating voltage applied to the exciter stator field has a phase rotation opposite that of the main rotor to ensure excitation from stand still up to full speed. Rotating part Stator winding Field winding Rectifier Exciter rotor winding Exciter stator winding Fig. 10 FE-model of the motor F. Rotor and excitation system design The fundamental frequency of the stator current and current harmonics will contribute to the magnetic field in the air-gap of the machine. They will also cause additional heating of the rotor pole iron. Because of the hazardous area classification for the motor, temperature class T3 (maximum surface temperature of 200 C (392 F)); it is of importance to calculate the losses and the temperature in the rotor pole iron. The calculation has been made using finite element analysis (FEA). Pole shoe surface temperature (deg.c) Rotor pole Pole surface length (mm) Fig. 11 The maximum pole shoe temperature during VSD from a finite element analysis The hazardous area requires a brush-less exciter, while the start of a variable speed motor requires application of excitation during stand still. Therefore the excitation system consists of a Fig. 12 Brush-less exciter for a variable speed motor The excitation system, including the brush-less exciter and excitation supply unit, is designed to give close to full rated torque during start-up. This allows full control during starting and operation of the motor. The optimal starting time depends on the requirement of the shaft system and electrical supply. Too long or too short starting time can increase the stress levels of the shaft. The air-gap flux level shall be kept constant up to 100% speed and field weakening is used between % speed. Figure 13 and 14 shows the different electrical and mechanical parameters such as flux, shaft torque and shaft power, exciter field current and main rotor field current. At zero speed the difference between exciter rotor frequency and stator frequency is least and therefore will exciter field current needed will be greatest at this operation point. Magnetic airgap flux and Shaft torque [pu] Flux Shaft power Shaft torque Speed [pu] Fig. 13 Magnetic air-gap flux, shaft torque and power during start and operation

8 Magnetic airgap flux and Shaft torque [pu] Exciter field current Main rotor field current Speed [pu] Shaft power Fig. 14 Main rotor and exciter field current and shaft power during start and operation VI. MOTOR PROTECTION For motor protection at different speeds, it was more suitable to incorporate the protection systems in the control system than to use standard machine protection. Standard protection system has often difficulty to work properly in a wide frequency range. The control system, which is now also used as motor protection, is redundant. This gives a safer operation and redundant protection. The protection set-up used for the VSD motor is shown in table I: Description TABLE I MOTOR PROTECTION Differential protection 87 ANSI code Overload and over current 49, 50/51 Negative sequence current 46 Harmonic overload 49, 51 Voltage-frequency (U/f) 24 Over speed/ Over frequency 12, 81H Stator ground fault 51G Locked rotor and long start 48 Over and under excitation 76, 37 Diode fault 58 The inverter station also protect for over voltage (59). VII. MOTOR TESTING The high voltage level of 56 kv requires special attention when performing motor testing at factory in respect of personal safety and test equipment. The variable drive system and control of the motor requires some special tests. The motor has a continuous operation window from 70 to 105% of rated speed; therefore the test must be performed at different speeds to verify the motor performance. Main motor breaker 72 kv Shortcircuit breaker Generator breaker 24 kv Reactor breaker 24 kv PT High voltage motor Test object CT MS Conventional Generator GS Reactor Motor neutral Driving motor M Driving motor M Fig. 10 Test set-up for 56 kv high voltage motor For temperature measurements 48 resistance temperature detectors (RTD) inside the stator slot and 36 RTDs at cable overhang (outside stator core) were installed, also 35 thermocouples (TC) in stator core lamination and 12 TCs in stator core end plates were installed. A total of 131 points of measuring was recorded during Heat-run tests. As expected the warmest parts were located inside the stator core, whereas the cable overhang (coil-ends) was relatively cool. The factory test room set-up requirements were: No-load test up to 76 kv (135% of rated line-to-line voltage) Sudden short-circuit test (determine transient reactance) Loss measurements with driving motor Loss measurements with retardation method Heat-run test driving motor and P.F.=0 Figure 10 shows the test set-up. Because of the voltage level was most of the test done with driving motor. The heat-run test has to be divided into three different test no-load, short-circuit and friction loss heat-run. Conventional machines are running at P.F.=0 at heat-run test. High voltage dielectric test was done up to 56 kv line-to-neutral, which correspond to a line-toline voltage of 97 kv. Standard test methods (according to IEEE 115, IEC and IEC [7] [8] [9]) have been used for most of the tests for the high voltage motor. Some of the tests performed are: Mechanical Balancing, Unbalance response, over speed and vibration Electrical characteristics, losses and excitation Stator impedance without rotor, no-load curve and no-load losses, short-circuit curve and short-circuit losses, sudden short-circuit, Negative and zero sequence reactance, high voltage (dielectric test)

9 Temperature No-load heat-run, short-circuit heat-run and friction heat-run Material Cold resistance, Insulation resistance measurement, Tan and partial discharge measurements Miscellaneous Sound level and Efficiency VIII. TEST RESULTS During the type test of the cable at a measuring voltage of 1.5 times rated line-to-neutral voltage (51.9 kv) was the partial discharge (PD) measured. The PD level was then less than 2.5 pc. At factory test on complete machine was also the PD level measured. The background noise was pc. No PD above noise level where detected. The balancing of the rotor was successful with only a small residual unbalances in he balance quality grade of ISO G0.32 (according to ISO 1940). Standard requirements is ISO G2.5 >> ISO G0.32. The API 546 requires a maximum residual unbalance of which corresponds to ISO G2.5. Vibration velocity levels for the two motors are measured in horizontal, vertical and axial direction. The average measured value is shown in table 2. The motor was design for an efficiency of 97.8%. The determined efficiency from test for sinusoidal feeding was 97.9% % for 70% to 105% speed. With regards to the estimated current harmonics during site operation the efficiency will be 97.8% %. Direction TABLE II VIBRATION LEVELS Measured average values [mm/s] Horizontal 0.8 < 1.8 Vertical 0.3 < 1.8 Axial 0.6 < 2.8 Exciter 0.9 < 4.5 IX. CONCLUSION Acceptance criteria [mm/s] Lesson learned from design phase: Design of skid system requires clear roles and responsibilities it may lead to increase in overall dimensions and weight Increased cooperation necessary to cover system design EEX (p) design is demanding for large electrical machines Results from tests in factory: Total losses below calculated Very low vibration levels EEX (p) test successfully completed In most cases, power supply to offshore installations from shore has been difficult or even impossible as long as the alternatives have been AC cables or classic line-commutated HVDC systems. VSC technology has enabled development of HVDC systems with converter stations that require smaller filters and no local generation or synchronous condensers, and with control properties far superior to those of classic HVDC. With a high-voltage cable wound synchronous motor is it possible to connect the motor with the HVDC transmission at the same voltage level. The bulky, heavy transformer between the two can therefore be avoided. Placing high voltage equipment on offshore installations poses some challenges, size and weight constraints are important. The motor and HVDC module can handle the special safety considerations and the harsh offshore environment. Using an HVDC transmission system and a high-voltage cable wound motor as a long distance electrical drive system has shown to be possible. X. REFERENCES [1] N. Hörle, K. Eriksson, A. Maeland, T. Nestli, "Electrical supply for offshore installations made possible by use of VSC technology", Cigré 2002 Conference. [2] M. Leijon et al., Breaking conventions in electrical power plants, in Cigré Session Report, 11/37-03, Paris, 30 August - 5 September, [3] M. Leijon, Powerformer - A radically new rotating machine, ABB Review, no. 2, 1998, pp [4] T. Trumbo, O. Forsell, J. O. Lamell, G. L.F. Porsby, C. Sundström, "42 kv Compressor Motor for Air Separation Plant in Sweden", PCIC [5] EN 50016:2002 E, Electrical apparatus for potentially explosive atmospheres Pressurized apparatus p, CENELEC. [6] IEEE Standard , Test Procedures for Synchronous Machines, IEEE. [7] IEC , Third edition, 1972, Rotating electrical machines. Part 2: Methods for determining losses and efficiency of rotating electrical machinery from tests (excluding machines for traction vehicles), IEC. [8] IEC , Second edition, 1985, Rotating electrical machines, Part 4: Methods for determining synchronous machine quantities from tests, IEC. XI. VITA Jan-Olof Lamell is a specialist in electrical design at ABB and has an MSc (EE) degree from the Royal Institute of Technology, Stockholm, Sweden. In 1994, he moved to the USA and worked on technical support and training of local sales/project managers. He moved back to Sweden in 1996 to work as a project manager and in 1999 joined the HV motor project, being responsible for the electrical design. He is a national member of Cigré study committee A1. Tim Trumbo graduated from Iowa State University in 1968, with a BSc degree in Engineering Operations. He has been an account manager with ABB Inc., Electrical Machines, since He is a member of the IEEE PCIC Transportation subcommittee and author of one previous PCIC paper. Tom F. Nestli received sivilingeniør (MSc) and Dr. ing. degrees from the Norwegian Institute of Technology in 1992 and 1996, respectively. His doctoral thesis was titled Modeling and Identification of Induction Machines and was based on research done in co-operation with ABB. Dr. Nestli was with ABB Corporate Research until he, in 2000, joined ABB s Automation Technologies Division as senior adviser and later project manager. Dr. Nestli is currently assistant project manager for the Troll A Pre-compression Electric Drive System project. Dr. Nestli is a Senior Member of the IEEE.