Ten years of operating experience with a 15000 hp, 6000 r/min adjustable speed drive system

Abstract

This paper is the sequel to a previous paper presented at the IEEE PClC Conference in 1994 [l]. . The original paper focused on the design, testing, and commissioning of-the 15 000 hp adjustable speed drive (ASD) system. This paper describes the operating experience of this ASD system during its first ten years of sewice. Several unplanned trips of the ASD, two failures of the input transformer, failure of the motor lead cables, and overheating of the motor that led to its eventual replacement are discussed. The incidents are described, the root causes are examined, the corrective measures are discussed, and the lessons learned are presented. The success of the ASD in dealing with the many utility voltage disturbances experienced by the refinery electrical system is also addressed. motor, operating experience, lessons learned.lndex Terms -Adjustable speed drive, ASD. high speed INTRODUCTIONThe ASD system is installed at the user's refinery located in Pascagoula. MS. The driven equipment is a hydrogen recycle centrifugal compressor in a benzene production facility. The ASD was originally started up in December 1993 and except for brief periods has been in continuous sewice since then.As described in more detail in [l], the high-speed motor (greater than 3600 dmin) and ASD were selected as a cost effective alternative to a steam turbine driver. Use of the ASD system avoided the need to purchase a new boiler and also had environmental and maintenance advantages. The existing electrical system had sufficient capacity to supply the new ASD system, so minimal capital investment in me electrical system was required. The high-speed motor was selected over a conventional speed motor with a gearbox to avoid the maintenance, torsional issues, and losses associated with the gearbox. The estimated capital cost savings of approximately $16 million dollars, along with the maintenance, environmental. and process control benefits, convinced project management to accept the ASD option over the steam turbine option. Even though the user's company had not applied large high-speed ASDs at that time, investigations concluded the technology was suitable for application in critical refinery sewice if the system was property designed, tested, commissioned, and maintained for reliability. Unfortunately, it would take several years after plant startup to complete this process. II. BASIC ASD SYSTEM DESIGNThe ASD system is a load commutated inverter (LCI) type drive which supplies a 15 000 hp synchronous motor. The basic ASD system design is discussed in more detail in [l] and will be only briefly described here. Fig. 1 shows a simplied diagram of the ASD system including the electrical system from which it is supplied.The input transformer is a three winding oil filled rectiier duty transformer with a delta primary winding and two three-phase secondary windings, one connected in delta and the other in wye, to provide suitable input to the 12-pulse line converter. It is rated 18.5 MVA at 65% rise and steps the voltage from 13.2 kV to 3.2 kV....

Passive filter design for a 12-pulse converter fed LCI-synchronous motor drive

“…However, there are many applications of LCI fed synchronous motor drives reported in the literature [19][20][21][22][23][24][25][26][27][28][29][30][31]. The applications of LCI-SM drive have been mainly for fans, compressors, pumps, grinders in petroleum or petrochemical industries, metal and cement industries, ship propulsion and rolling mills.…”

Particle swarm optimisation for power quality improvement of a 12-pulse rectifier-chopper fed LCI-synchronous motor drive

“…There are very few publications (Frey, 1991;Villablanca et al, 1992;Zayechek, 2000;Villablanca et al, 2001;Wood et al, 2004;Simond et al, 2005) available in the literature regarding the power quality improvement in LCI-SM drives. Conventional three-phase SM fed from two LCIs using a phase shifting transformer or six phase SM fed from two LCIs have also been reported (Dugan et al, 2004;Wood et al, 2004) for harmonic mitigation.…”

“…The selection of a 12-pulse rectifier configuration for LCI-SM drive amongst a number of configurations of multipulse AC-DC converters (Frey, 1991;IEEE Standard 519 (1992); Villablanca et al, 1992;International Standard IEC 61000-3-2, 2000;Zayechek, 2000;Wood et al, 2004) is due to its benefit of lowest switch count. However, a 12-pulse rectifier configuration has various harmonic components; therefore, an optimised passive filter combination is required to be connected at the input mains to achieve an improved power quality comparable to higher pulse AC-DC converters.…”