Loss‐of‐excitation analysis and protection for pumped‐storage machines during starting

Dynamic safety assessment of a nonlinear pumped-storage generating system in a transient process

“…A nonlinear PSGS can at least operate in twenty-four switching modes [12][13][14] during which transient processes such as the loss of pump-power, the load rejection and pump shutdown may occur. The relative opening of closing law 1 and 2 for the 30-seconds transient time is illustrated in Fig.…”

“…PSGSs are complex nonlinear systems incorporating a great deal of uncertainty in the operation of their hydraulic, mechanical and electrical components [8][9][10][11]. Based on five fundamental conditions (i.e., static, generating and pumping condition as well as generating/pumping transfer to phase modulation), PSGSs provide twenty-four switching modes such as start-up in pumping/generating condition switch to shut-down, start-up in pumping/generating condition switch to load rejection, and static switch to pumping condition due to the different demands of the electricity generation in hydropower stations [12][13][14]. This results in a substantial level of safety challenges such as vibration and water hammer pressure amplitudes in the penstock and draft tube [15][16][17][18][19].…”

Fault Studies and Distance Protection of Transmission Lines Connected to DFIG-Based Wind Farms

“…These values are substituted into Equation (12) to obtain a series of difference equations. Then, the equations are solved with the least-squares method [35]. Set the sampling period to be T s .…”

Three‐phase battery storage system with transformerless cascaded multilevel inverter for distribution grid applications

“…The PWM transfer function is given by (9), where v tp is the peak value of the triangular carrier and its value is equal to one…”

“…Storage applications in medium-voltage grids have been described in the literature [9][10][11][12]. In [9], a pumped storage with loss of excitation protection is presented while in [10] a doubly-fed induction-machine-based flywheel energy storage system is introduced. In [11], a battery energy storage system is aggregated to a wind generator (WG) system in order to damp power oscillation produced by the WG system.…”