Pulse Width Modulated Variable Speed Drives used in Electrical Submersible Pump applications produce high order harmonics that interact with inherent system resonant points to produce severely amplified system voltages on connected down hole systems. Every ESP application has a resonant point that is a function of the transformer, cable and motor impedance. As this impedance increases it lowers the resonant point until it reaches the point that it coincides with the VSD carrier frequency or one of its multiples. As the system resonates it produces system voltages that can easily be 5 times higher than the operating frequency of the VSD. This elevated voltage easily damages the insulation systems of the connected equipment and causes early equipment failure. By connecting a SUB-E-725 Load Filter to the high voltage terminals of the step up transformer the resonant point can be shifted well below the carrier frequency. This attenuates (reduces) any amplification that can occur and brings system voltages back to within equipment design specifications. What this translates to is increased run time and fewer down hole failures. Application of the SUB-E-735 filter produces cleaner sine wave voltages for the ESP and reduces the effects of heating due to harmonics. currentssble to build a computer model of the system to determine how load is distributed and then offer solutions to make each system as efficient as possible. The return for the client is a system that is very economical to run while displaying fewer operational problems and failures. Through the use of ETAP software SUBCOE is able to:
The oscilloscope readings above show how system voltages react before and after the installation of the SUB-E-725 output filter. SUBCOE's SUB- E-725 is rated at 5.3 kV, is configurable to suit varying cable lengths and pump depths, and contains controls to prevent filter overloading during operation. |
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