New breakthrough in application of FGI Medium Voltage Drive in high speed permanent magnet submersible electric pump
1.Summarize
High speed permanent magnet submersible pump is a kind of high efficiency and energy saving oil production equipment, its core components include high speed permanent magnet motor, centrifugal pump, submersible cable and control system, etc. The energy saving effect is better when using high speed permanent magnet direct drive system, which can achieve 20%~30% energy saving effect. The electric submersible pump is a multistage centrifugal pump that works in the well and runs into the well together with the tubing. The ground power supply transmits the electric energy to the downhole submersible motor through the frequency converter, so that the motor drives the multistage centrifugal pump to rotate and lift the well fluid to the surface. Submersible cable as the channel part of the electric pump unit to transport electric energy, long-term work in high temperature, high pressure and corrosive fluid underground environment, generally using long distance flat cable, cable length 2000-3000 meters.
2.Electric machine parameter
3.Technical essential
Difficult to start
High voltage and high speed permanent magnet synchronous motor direct drive, the traditional starting impulse current is large, difficult to achieve smooth starting, affecting the service life of submersible electric pump.
The cable voltage drop is large
Submersed cable distance of about 2000 meters, line impedance is large, carrying current through will produce obvious voltage drop, the actual motor terminal voltage is lower than the rated voltage, affecting the normal operation of the motor.
Voltage distortion
The output PWM wave is transmitted through a long cable, and due to the influence of the distributed inductance and distributed capacitance of the cable, overvoltage and harmonics will be generated at the motor end, which may lead to over-voltage or over-current protection of the inverter, and even breakdown the insulation layer of the motor and damage the motor.
Motor parameter identification problem
Due to the influence of line impedance, the identification of motor parameters is difficult, and the high-speed submersible motor and cable run in the deep well environment of high temperature and high humidity, the motor parameters change obviously, and the motor is easy to lose control.
4.Field application
The frequency converter control strategy of FGI high voltage permanent magnet synchronous motor is a high-performance position senser-free vector control technology. It adopts efficient speed/flux observation algorithm to accurately calculate the magnetic pole position of the permanent magnet synchronous motor, and adopts current feedback to achieve current closed loop and weak magnetic control, effectively compensating the cable voltage drop, and has good speed and current tracking performance. To ensure the stable operation of the high-speed constant power zone, the high-speed permanent magnet motor has a wider speed range.
High-speed no-load operation data of submersible motor
Submersible motor 215Hz oil pump full load and no load operation data
Submersible motor 215Hz oil pump full load A-phase current monitoring waveform
5.Summarize
The medium voltage drive effectively solves the problem of large impedance voltage drop caused by long cables, and realizes the stable starting process of the high speed permanent magnet submersible pump motor.
Medium voltage drive adopts high speed permanent magnet synchronous frequency conversion mode, wide speed range, high precision, can adjust the frequency according to the actual field flow demand, energy saving effect is remarkable, can reach 20%~30% energy saving effect.
The Medium voltage drive can realize the detection of underload protection, overload protection, stall protection, etc., which can avoid the oil pump damage caused by stuck pump, long-term no-load idling, pump power overload, etc., and can improve the service life of the oil pump.
One-time debugging and on-load operation successfully, fully meet the actual operation needs of the site, won the praise of customers.
