Events

PCIC Middle East

February 26-27, 2019
Abu Dhabi, UAE

 

The PCIC Middle East Petroleum & Chemical Industry Conference supports the exchange of technical experience in electrical and instrumentation in the oil & gas, chemical and pharmaceutical industries.

What is PCIC? PCIC stands for the Petroleum and Chemical Industry Conference.

PCIC Middle East is the regional representation of PCIC Europe to organize the premier Conference for the exchange of experience in electricity and instrumentation in the oil & gas, chemical and pharmaceutical industries, covering all the aspects of the upstream and downstream activities.

The PCIC Middle East and PCIC Europe conferences mobilize experts from:

  • End-users
  • Engineering companies, Contractors and Manufacturers
  • Certifications Authorities, Standardization organizations, Regulation Authorities

The experts gather to present technical papers and and lead panels discussions to share their experience and good practices with the attendees.

The subjects are selected for the conference by a Technical Committee because of their high value for the companies operating in the Middle East region in order to provide immediate benefits to attendees.

InterContinental Hotel – Abu Dhabi
Abu Dhabi King Abdullah bin Abdulaziz Al Saud St, King Abdullah bin Abdul Aziz, Abu Dhabi 4171

  • Tuesday, February 26, 2019
  • Wednesday, February 27, 2019

 

Beckwith Technical Presentation


Motor Bus Transfer Applications Issues and Considerations

  • Tuesday, February 26, 2019
  • 10:30 AM-Noon
  • InterContinental Hotel, Abu Dhabi, UAE
  • Presenters:
    • Tom Beckwith
      CEO

This technical paper explores the following research:

  • Residual Voltage Transfers always thought to be safe even if completed out-of-phase, can cause significant torques on motors, exceeding a 3-phase fault at the motor terminals.
  • IEEE C37.96 identifies events that occur or conditions that exist prior to and during transfer where, at transfer initiate, the initial phase angle may be nowhere near zero!
  • So at the end of a Residual Voltage Transfer spin down, the close phase angle may be nowhere near zero!
  • Research with modeling motors during transfer has proven that in 40% of the cases closing at varied angles, the peak-to-peak torques developed during the Residual Voltage Transfer are higher than the 3-Phase Short Circuit Torques of the motors on the bus.
  • This research has revealed that the peak currents in motors during Residual Voltage Transfers are higher than the 3-Phase Short Circuit Currents in more than 60% of these cases.
  • This motor modeling research also shows that in 89% of the cases closing at varied angles, the currents during Residual Voltage Transfer are in excess of six times rated current.
  • Synchronous In-Phase Transfers may take longer than some arbitrary time limit. Depending on the initial phase angle at transfer initiate, it may take more than 6 or 10 cycles for the motors to rotate back into synchronism.
  • Compared to blind Residual Voltage Transfers, these Synchronous In-Phase Transfers are much faster, closing at much higher voltages, at much lower slip frequencies, with closure near zero degrees and low inrush current and torque.
  • The 1.33 resultant pu V/Hz transfer criterion in NEMA MG-1, ANSI/NEMA C50.41 and IEEE C37.96 has no correlation to motor torque and actually gives passing grades to severely excessive torques upon transfer.
  • Time period transfer criteria, stated in NEMA MG-1, IEEE 666, ANSI/NEMA C50.41 and IEEE C37.96, are arbitrary and would permit severely out-of-phase transfers or conversely may preclude perfectly good synchronous transfers.
  • A Motor Torque Ratio TPK /TL, introduced as the aggregate peak torque at transfer expressed as a multiple of the aggregate load torque prior to transfer, displays a high correlation to the phase angle at transfer with little effect from voltage or frequency difference.
  • If it is torque that reduces the life expectancy and damages motors or driven equipment, or both, as suggested in the C50.41 Standard, then the industry must use a torque-based criterion to assess if transfers are being completed within acceptable torque limits.