The growing installation of distributed energy resources (DER) in the network allows an active interaction between the transmission and distribution system operators. This interaction is possible mainly by the power electronic converters (PECs) incorporated in the DER, used as an interface with the network. The PECs, also known as smart inverters, offers excellent controllability features and allow DER to provide procurement services to the distribution and transmission network. This paper focuses on evaluating the reactive power control features of the smart inverter considering eight control local modes following the IEEE 1547-2018 standard. Moreover, it is proposed an optimal reactive power controller able to minimise the active power losses in the network by optimally adapting the reactive power injection/absorption of the smart inverter. This optimal controller ensures all the busbar voltages are inside the permissible limits, and the reactive power limits of the smart inverter are enforced. The Vestfold and Telemark distribution network model was implemented using DIgSILENT PowerFactory to evaluate the optimal and the eight local reactive power control modes. Simulation results show the proposed optimal reactive power control is the best option to offer the service of active power loss minimisation using smart inverters for the daily steady-state performance of the DSO network.@en

The transition to a low-carbon society is the driving force pushing the traditional power system to increase the volume of non-synchronous technologies which mainly use power electronic converters (PEC) as an interface to the power network. Today, PEC is found in many applications ranging from generation, transmission, storage, and even active loads and protections. The variety of types, applications is almost unlimited. However, the behaviour of PEC is radically different to the typical devices used in traditional power systems, and its specificity in terms of control, overload characteristics, etc. entails an entirely different approach for modelling and simulation. This chapter presents a general review of the main concepts related to power electronic converters and their implementation in DIgSILNET PowerFactory. The chapter finalises with a discussion about the modern tendencies in power electronic applications in power systems: grid following and grid-forming converters.

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Mongolian power grid (MPG) is becoming more eco-friendly as the power system is continuously integrating renewable energy, which reached 20% of the total installed capacity of Mongolia in 2020. The daily operation and the safety of the MPG have become very challenging because of increased levels of energy in the system. Therefore, the dynamic behaviour of conventional power plants (CPPs) must be demonstrated to fulfil the requirements of integrating more renewable energy in the MPG, especially for frequency stability. This paper illustrates the results of the system parameter identification of an actual steam turbine and a governor system with PID controller by using a real-life test performed on Generator 1 (G1) of the biggest thermal power plant (TPP-4) in Mongolia on 6^th March 2020. The main contribution of this paper is to clear uncertainties about the PID controller's parameters installed in the steam turbine of G1 in early 2019, consequently giving the system operator an accurate dynamic model of the generation unit. The steam turbine and governor are modelled in DIgSILENT® PowerFactory, and the Particle Swarm Optimization (PSO) method is used for identifying the parameters of the PID controller of the G1 at TPP-4. Simulation results from the PowerFactory software matched firmly (error <0.3%) with the measured frequency from the Phasor Measurement Unit (PMU).@en