Question

what is the Power Electronics Applications in the electric grid in KSA

Answer 1

The electric grid is continuously going through an evolutionary process with growing penetration of intermittent renewable power, multi-directional power flow, and demand-side management based on real-time data.

In the electric grid nearly 70% of power transformers are 25 years or older and roughly 60% of circuit breakers are 30 years or older. To protect transformers, circuit breakers power electronics plays a vital role in the power systems

Power electronics as a tool for grid modernization:

1) Solid State Transformers:There are some prototypes developed using SiC-based semiconductor devices. General Electric has developed a 13.8kV/265kV 1MVA SST which uses 10kV SiC MOSFETs operating at 20kHz frequency

2) UHVDC and multiterminal DC grid:VSC based systems still lack in terms of on-state losses hence they still are not a strong contender for long distance UHVDC systems. Silicon based high power thyristors have served the industry for over four decades through a continuous evolution of voltage and current ratings. Now, thyristors with highest voltage withstand limit of 8.5 kV and current rating up to 6kA are used commercially ever, Silicon-based thyristors are reaching the physical limit in terms of blocking voltage capability, current and rate of change of voltage. As discussed in the last section, wide-bandgap SiC is a promising alternative which can overcome the limitation of Si based devices.With such fast developments in SiC based devices, ultra-high voltage SiC thyristors are promising for next generation of HVDC converters.

3)Synthetic Grid Inertia:

To mitigate the loss of inertia, power electronics can be used to mimic the operation of conventional power plants and provide ‘virtual’ or ‘synthetic’ gird inertia. As discussed earlier that grid inertia can be modelled as stored mechanical energy, so energy storage devices like batteries, flywheels, and supercapacitors along with power electronics-based inverters can be utilised to fulfil the missing rotational inertia specifically in solar applications. In case of wind turbines, where kinetic energy exists at variable speed, advanced control techniques are proposed to emulate the behaviour of synchronous generators. Grid inertia support through power converters can change the perception of renewables from a liability to a contributor towards grid stability.