With 50 years of experience, G B
Subsea Limited builds and
supplies state of the art
electrical distribution and
power transformers, built with
the finest quality materials
using most advanced
manufacturing technology and
tested according to the NTC,
ANSI or IEC standard established
tests.
G B Subsea Limited
created and developed its own
Computer-Aided Design and
Calculation System for
transformers, which allows to
obtain the most economical
alternative, according to the
customer’s needs,
following the requirements of
the standards and the
reliability concept of the
equipment.
Electrical Distribution & Power Transformers
Step Up Transformers (SUT)
The Electrical Submersible Pump (ESP) system is intended to lift large volumes of fluids in an efficient and cost-effective manner. Several variables in the lifting process affect the production level. The variable speed drive (VSD) enables the operator to control performance of the ESP system, changing the speed of the motor installed at the bottom of the well, by making changes in the frequency.
Motors installed at the bottom
may generate a maximum torque
depending on the voltage applied
to their terminals at a given
frequency. Due to the
differences in fluid properties,
it is necessary to vary the
motor speed in order to obtain
the maximum torque; this is
achieved by modifying the
voltage applied at the motor
terminals. This is one of the
reasons for using VSD in ESP
systems.
Typically, VSD
output voltages are lower than
those required by the ESP system
motor for optimal operation. In
addition, since the VSD
operating frequency varies
depending on the well
characteristics and, given that
the VSD wave contains harmonics,
use of a conventional
transformer is not possible in
these cases. For these reasons,
a special step-up transformer
must be used.
Phase Shift Transformers (PST)
The many benefits of variable speed drives (VSD) in ESP pumping systems have led to exponential growth in the use of these devices in production fields handling high fluid output levels. The use of VSDs causes some difficulties when connected to the electrical power system; due to the fact that static power converters produce non-linear loads, affecting the natural sine shape of alternating current, introducing hamonic currents into the electric power network that could cause interference in the communication circuits and damage the equipment installed on the network.
Specially designed Phase Shift Transformers (12 Pulse & 24 Pulse) mitigate the effect of speed drives when connected to the network, by reducing the harmonics reaching the electrical netwrok, depending on the number of pulses of the VSD. The harmonic distortion is mitigated by incresing the number of rectifying sections used in the VSD.
SKID
The ESP system can be divided
into two main equipment groups,
located downhole and at the
surface, and connected to each
other by a power cable.
The
need to protect people and the
environment, while maximizing
operational functionality of the
surface equipment led to the
development of Skids for this
specific application.
