The ESP Step-up Transformer ( TMPN ) matches the VSD output voltage with the downhole motor (PED) requirements using multiple manual voltage taps.
It acts as a critical link in the electrical chain, converting low input voltage from the control panel into the high voltage necessary for efficient power transmission over long distances.
Purpose and Function
The main purpose of the TMPN (an acronym for Oil-filled Transformer for Submersible Pumps) is to step up the voltage from 380V (or 480V) to a range typically between 1000V and 6000V. This is essential to:
- Compensate for voltage drops in long power cables.
- Provide the specific nameplate voltage required by the downhole motor.
- Voltage Taps: Unlike standard industrial transformers, the TMPN is equipped with multiple output taps. This allows field engineers to manually adjust the output voltage (e.g., in 50V or 100V increments) to compensate for varying cable lengths or motor specifications.
- Oil-filled Construction: The transformer is filled with dielectric oil for cooling and insulation, making it suitable for continuous outdoor operation in extreme environments.
- Expansion Tank: Most units feature an external expansion tank to manage oil volume changes due to temperature fluctuations during operation.
The TMPN is usually positioned between the Variable Speed Drive (VSD) and the wellhead. During commissioning, selecting the correct tap is vital:
- Undervoltage: Leads to insufficient torque and motor stalls.
- Overvoltage: Causes excessive motor heating and insulation breakdown.