Flexibility of Generator and Converter

About

Work package 4 addresses the issues relating to starting (both pumping and generating mode) and operation of the converter driven pumped storage unit. The starting will be improved/smoothed with the help of the converter, and the operation enhanced via regulating systems that will provide strong ancillary services to the grid and minimize component wear. The goal is to arrive at a system that combines the converter and synchronous machine with magnetization system and smart control and insulation that copes with the switched power supply.

Objectives

• Develop a synchronous generator rotor design with high efficiency for variable speed operation and tailored low-loss multilevel converters
• Develop high power frequency converter and configuration for power station performance and costs
• Optimized joint control of converter and rotor magnetization to optimize performance and provide a robust grid connection with good fault ride through capabilities
• Develop simulation models for investigation of the capability of the power station to stabilize the power grid during major disturbances, and to investigate the capability to keep the power station connected during major grid disturbances
• Present an insulation system with improved field grading design that can mitigate the effect from high power electric converter fast voltage switching long term. Make the effect of over-harmonics from high power electronic converters insignificant for the service lifetime of the generator insulation- and end winding system

Tasks

4.1. Grid interface and grid code adherence and support

The main objective of this task is to conduct power system integration studies to establish control strategies and procedures that give hydropower plants with the proposed generator and converter technology robust Fault Ride Through capability and the ability to provide balancing and ancillary services to transmission system operators.

4.2. New generator rotor system concept for low loss variable speed operation and improved torque control through current controlled magnetization system

This task aims to develop a common action plan for the frequency converter and the rotor magnetization to optimize performance during startup and pumping, but also during synchronized generation. This will be tested with our industry partner.

4.3. Power electronic interface

The inverter for the hydro generator provides substantial new possibilities for a flexible driving of the whole electric drive train system, and accordingly the generator and the inverter will in this project be derived in parallel.

4.4. Enhanced generator winding insulation system and performance testing

This task includes electromagnetic modelling and analysis of the voltage distribution inside and the winding and experimental characterization of the field grading material as function of applied voltage and frequency.

Participants

Work package 4 is led by the Division of Electricity at the Department of Engineering Sciences, Uppsala University.

Contact: Prof. Urban Lundin

Partners:

• NTNU 
• UU (Leading Task 4.1 and 4.2)
• CHALMERS (Leading Task 4.3)
• SINTEF  (Leading Task 4.4)
• RP
• USTRAT
• ABB AS