Active filters differ from passive filters in that they do not generate overvoltages upon connection, as they do not similarly trap charge in capacitors. The standard configuration of an active filter includes an inductor, such as a filter coil, and a power electronic converter, which comprises switches and capacitor energy storage.
The active filter converter is usually managed to generate harmonic waveforms in opposite phases, thereby reducing or eliminating harmonic propagation. Besides harmonic filtering, active filters can also be utilized to correct the power factor. In future applications, active filter functions, such as harmonic filtering and power factor correction, may be integrated into the grid-side control of energy storage systems.
Consequently, the administration of an active filter through SCADA and NIS/DMS systems may serve as a model for managing energy storage applications.
Management systems and the communication architecture of MV/LV transformer stations with energy storage are depicted in Figure 1.
The envisioned communication architecture relies on the public internet, encompassing Ethernet and IP protocols, gateway transformers, and the local IP network within the MV/LV transformer station and the control centre. This IP network facilitates the use of various protocols, which are applicable to energy trading, storage management configuration, remote control, power quality monitoring, and web-based services.
An encrypted Virtual Private Network (VPN) can be utilized to tunnel traffic through a public network securely.
Standard IEC protocols are utilized for controlling distributed resources and filters. The intelligent logical device for energy storage can be modeled using the object-oriented structure and architecture as defined in IEC 61850, along with its subsequent additions.
Advanced management applications for energy storage, such as battery management, can be web-based and accessible through the NIS/DMS system. Communication with the energy storage system includes configuring the storage and managing energy trade applications. Additionally, power quality measurements from the energy storage can be utilized in a power quality database, within the NIS/DMS system, and in SCADA systems.
The SCADA schematic diagram depicted in Figure 2 illustrates a medium voltage/low voltage (MV/LV) transformer station equipped with an active filter. The diagram includes symbols representing the ring unit's disconnectors, the transformer's disconnectors, the transformer itself, the low voltage (LV) busbar relay, the LV feeders' fuse-switches, and the active filter feeder's relay.
Additionally, the active filter (highlighted in red) along with potential measurements and indicators are displayed.
Figure 2 illustrates the SCADA schematic diagram of an MV/LV transformer station equipped with an active filter. On the right, examples of potential variables, alarms, and warnings associated with an active filter are shown.
Extensive monitoring of low-voltage processes and power quality indices through SCADA systems involves a large number of points for both measured and calculated values.
The cost of SCADA products is determined by the required number of points. So far, this pricing structure has enabled both small and large distribution companies to afford updates to their SCADA systems. However, to facilitate large-scale, multi-value LV monitoring, innovative pricing models for SCADA and NIS/DMS will be necessary.
Implementing a pricing model that does not rely on point count could remove the need for superfluous virtual groupings, structures, and the condensation of low-voltage information. For example, a relational database is capable of managing vast databases, and the processing and memory capacities of information systems have grown exponentially.
Additionally, as high-speed networks become more accessible and continue to advance rapidly, the real bottleneck may indeed be the cost of SCADA products.
Guide: | Intelligent distribution automation of MV/LV transformer stations at LV networks Johan Nyberg |
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Pages: | 187 |
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