Wind Power Plant Short Circuit Current Contribution for Different Fault and Wind Turbine Topologies: Preprint

This paper presents simulation results for SC current contribution for different types of WTGs obtained through transient and steady-state computer simulation software

Validation of Wind Power Plant Dynamic Models: Preprint

This paper discusses the process of wind model validation against field measurements

Wind Farm Aggregation Impact on Power Quality: Preprint

This paper explores the effects of wind farm power fluctuations on the power network. A dynamic simulation of a wind farm is performed and the spatial distribution of the wind turbines is considered

Symmetrical and Unsymmetrical Fault Currents of a Wind Power Plant: Preprint

This paper investigates the short-circuit behavior of a wind power plant for different types of wind turbines. Both symmetrical faults and unsymmetrical faults are investigated. The size of wind power plants (WPPs) keeps getting bigger and bigger. The number of wind plants in the U.S. has increased very rapidly in the past 10 years. It is projected that in the U.S., the total wind power generation will reach 330 GW by 2030. As the importance of WPPs increases, planning engi-neers must perform impact studies used to evaluate short-circuit current (SCC) contribution of the plant into the transmission network under different fault conditions. This information is needed to size the circuit breakers, to establish the proper sys-tem protection, and to choose the transient suppressor in the circuits within the WPP. This task can be challenging to protec-tion engineers due to the topology differences between different types of wind turbine generators (WTGs) and the conventional generating units. This paper investigates the short-circuit behavior of a WPP for different types of wind turbines. Both symmetrical faults and unsymmetrical faults are investigated. Three different soft-ware packages are utilized to develop this paper. Time domain simulations and steady-state calculations are used to perform the analysis

Variable Frequency Operations of an Offshore Wind Power Plant with HVDC-VSC: Preprint

In this paper, a constant Volt/Hz operation applied to the Type 1 wind turbine generator. Various control aspects of Type 1 generators at the plant level and at the turbine level will be investigated. Based on DOE study, wind power generation may reach 330 GW by 2030 at the level of penetration of 20% of the total energy production. From this amount of wind power, 54 GW of wind power will be generated at offshore wind power plants. The deployment of offshore wind power plants requires power transmission from the plant to the load center inland. Since this power transmission requires submarine cable, there is a need to use High-Voltage Direct Current (HVDC) transmission. Otherwise, if the power is transmitted via alternating current, the reactive power generated by the cable capacitance may cause an excessive over voltage in the middle of the transmission distance which requires unnecessary oversized cable voltage breakdown capability. The use of HVDC is usually required for transmission distance longer than 50 kilometers of submarine cables to be economical. The use of HVDC brings another advantage; it is capable of operating at variable frequency. The inland substation will be operated to 60 Hz synched with the grid, the offshore substation can be operated at variable frequency, thus allowing the wind power plant to be operated at constant Volt/Hz. In this paper, a constant Volt/Hz operation applied to the Type 1 wind turbine generator. Various control aspects of Type 1 generators at the plant level and at the turbine level will be investigated

Control strategy for variable-speed, stall-regulated wind turbines

A variable-speed, constant-pitch wind turbine was investigated to evaluate the feasibility of constraining its rotor speed and power output without the benefit of active aerodynamic control devices. A strategy was postulated to control rotational speed by specifying the demanded generator torque. By controlling rotor speed in relation to wind speed, the aerodynamic power extracted by the blades from the wind was manipulated. Specifically, the blades were caused to stall in high winds. In low and moderate winds, the demanded generator torque and the resulting rotor speed were controlled to cause the wind turbine to operate near maximum efficiency. A computational model was developed, and simulations were conducted of operation in high turbulent winds. Results indicated that rotor speed and power output were well regulated. 7 refs., 7 figs

PSCAD Modules Representing PV Generator

Photovoltaic power plants (PVPs) have been growing in size, and the installation time is very short. With the cost of photovoltaic (PV) panels dropping in recent years, it can be predicted that in the next 10 years the contribution of PVPs to the total number of renewable energy power plants will grow significantly. In this project, the National Renewable Energy Laboratory (NREL) developed a dynamic modeling of the modules to be used as building blocks to develop simulation models of single PV arrays, expanded to include Maximum Power Point Tracker (MPPT), expanded to include PV inverter, or expanded to cover an entire PVP. The focus of the investigation and complexity of the simulation determines the components that must be included in the simulation. The development of the PV inverter was covered in detail, including the control diagrams. Both the current-regulated voltage source inverter and the current-regulated current source inverter were developed in PSCAD. Various operations of the PV inverters were simulated under normal and abnormal conditions. Symmetrical and unsymmetrical faults were simulated, presented, and discussed. Both the three-phase analysis and the symmetrical component analysis were included to clarify the understanding of unsymmetrical faults. The dynamic model validation was based on the testing data provided by SCE. Testing was conducted at SCE with the focus on the grid interface behavior of the PV inverter under different faults and disturbances. The dynamic model validation covers both the symmetrical and unsymmetrical faults

Soft-Stall Control versus Furling Control for Small Wind Turbine Power Regulation

Many small wind turbines are designed to furl (turn) in high winds to regulate power and provide overspeed protection. Furling control results in poor energy capture at high wind speeds. This paper proposes an alternative control strategy for small wind turbines -- the soft-stall control method. The furling and soft-stall control strategies are compared using steady state analysis and dynamic simulation analysis. The soft-stall method is found to offer several advantages: increased energy production at high wind speeds, energy production which tracks the maximum power coefficient at low to medium wind speeds, reducing furling noise, and reduced thrust

A conservative control strategy for variable-speed stall-regulated wind turbines

Simulation models of a variable-speed, fixed-pitch wind turbine were investigated to evaluate the feasibility of constraining rotor speed and power output without the benefit of active aerodynamic control devices. A strategy was postulated to control rotational speed by specifying the demanded generator torque. By controlling rotor speed in relation to wind speed, the aerodynamic power extracted by the blades from the wind was manipulated. Specifically, the blades were caused to stall in high winds. In low and moderate winds, the demanded generator torque and the resulting rotor speed were controlled to cause the wind turbine to operate near maximum efficiency. Using the developed models, simulations were conducted of operation in turbulent winds. Results indicated that rotor speed and power output were well regulated. Preliminary investigations of system dynamics showed that, compared to fixed-speed operation, variable-speed operation caused cyclic loading amplitude to be reduced for the turbine blades and low-speed shaft and slightly increased for the tower loads. This result suggests a favorable impact on fatigue life from implementation of the proposed control strategy