Experimental Assessment of a Centralised Controller for High-RES Active Distribution Networks

Abstract

This paper assesses the behaviour of active distribution networks with high penetration of renewable energy sources when the control is performed in a centralised manner. The control assets are the on-load tap changers of transformers at the primary substation, the reactive power injections of the renewable energy sources, and the active and reactive power exchanged between adjacent feeders when they are interconnected through a DC link. A scaled-down distribution network is used as the testbed to emulate the behaviour of an active distribution system with massive penetration of renewable energy resources. The laboratory testbed involves hardware devices, real-time control, and communication infrastructure. Several key performance indices are adopted to assess the effects of the different control actions on the system’s operation. The experimental results demonstrate that the combination of control actions enables the optimal integration of a massive penetration of renewable energy.

State Estimation for Hybrid VSC Based HVDC/AC Transmission Networks

“…• a has a typical value of 11.033 × 10 −3 pu and it represents the no load losses of transformers and averaged axillary equipment losses, such as heating and cooling losses; • b has a typical value of 3.464 × 10 −3 pu and it represents the switching losses of valves and freewheeling diodes; • c represents the conduction losses of the valves and depends on the operating condition of the converter (rectifier or inverter). it is typical values are: c = 4.4 × 10 −3 pu, for rectifiers 6.67 × 10 −3 pu, for inverters (22) In addition to the converter losses themselves (P convloss ), there are the AC side transformer, filter and reactor (Transformer, Filter and Reactor (TFR)) losses as shown in Figure 5. In this work, the TFR term is used to refer to these losses as part of the AC grid.…”

“…The same architecture is used with the HVDC stations and transmission grids, they are operated by separate SCADA systems as shown in Figure 1 [1][2][3][13][14][15]. As a result, the research on SCADA for hybrid HVDC/AC transmission (mainly VSC based) is divided into two main approaches, a distributed or decentralized approach such as in [16][17][18][19], and centralized or hierarchical structure such as in [1,2,[20][21][22]. In the centralized approach, both AC and DC sides are controlled by one unified SCADA, leading to several challenges and modifications have to be addressed such as:…”

Ancillary Services in Hybrid AC/DC Low Voltage Distribution Networks

“…In those situations, controlling the voltage by means of reactive power injection is not a cost-effective solution, which prevents the use of large utility-scale devices or oversized distributed generators. Undoubtedly, a coordinated control of all these resources is the best option to provide the voltage regulation within the AC distribution system [94].…”

Methods and Concepts for Designing and Validating Smart Grid Systems

“…For this purpose, the development, the structure and the operation of a corresponding hardware-based lab test stand was described. In a further laboratory setup, the behaviour of active distribution networks was analysed, which were strongly penetrated by renewable energies [16]. This was examined by means of various parameters (tap changers of the transformers in the primary substation, reactive power injections of the renewable energy sources and active and reactive power exchanged between adjacent feeders being interconnected through a direct current link), to show what an optimal control can look like.…”