Fault Ride-Through of Large Wind Farms Using Series Dynamic Braking Resistors (March 2007)

Abstract

Fault ride-through (FRT) is required for large wind farms in most power systems. Fixed speed wind turbines (FSWTs) are a diminishing but significant sector in the fast-growing wind turbine (WT) market. State-of-art techniques applied to meet grid requirements for FSWT wind farms are blade pitching and dynamic reactive power compensation (RPC). Blade pitching is constrained by the onerous mechanical loads imposed on a wind turbine during rapid power restoration. Dynamic RPC is constrained by its high capital cost. These present technologies can therefore be limiting, especially when connecting to smaller power systems. A novel alternative technology is proposed that inserts series resistance into the generation circuit. The series dynamic braking resistor (SDBR) dissipates active power and boosts generator voltage, potentially displacing the need for pitch control and dynamic RPC. This paper uses a representative wind farm model to study the beneficial effect of SDBR compared to dynamic RPC. This is achieved by quasi-steady-state characterization and transient FRT stability simulations. The analysis shows that SDBR can substantially improve the FRT performance of a FSWT wind farm. It also shows that a small resistance, inserted for less than one second, can displace a substantial capacity of dynamic RPC.

Overview of condition monitoring and operation control of electric power conversion systems in direct-drive wind turbines under faults

“…The parameters of the current control loop and fieldweakening control loop were designed by the eigenvalue method for state-space equations, in consideration of the large inertia property of DD-WTs. In addition, excitation losses of different degrees occur in PMSG rotors as the service time of DD-WTs extends [135]. Similar to the weak magnetic principle of permanent magnets, i d is used to increase the magnetic field to realize instantaneous excitation loss or partial demagnetization for reliable operation.…”

Transient stability enhancement of DC-connected DFIG and its converter system using fault protective device

“…A bridge-type fault current limiter (BFCL) has been proposed to enhance the transient stability of DFIGs, which is a promising application in an AC grid [18][19][20][21], but it only suits specific situations. A SDBR has a simple structure, which is applied in both AC and DC grids to enhance the transient stability and fault ridethrough capability of generators [22][23][24], but it cannot overcome both overcurrent and overvoltage issues and current impulse usually occurs.…”

An improved efficiency of fuzzy sliding mode control of permanent magnet synchronous motor for wind turbine generator pumping system

“…At the early stage, only DC motors were used to drive pumps. Direct coupling of series, shunt, and separately exited DC motor Wind Turbine Generator pumping systems were studies [6,7]. It was found that the overall performances are totally different from those obtained when these motors are connected to a constant voltage source.…”