The article is focused on the issue of blackouts in a water industry and the selection of a renewable energy source for a water treatment plant. In the case of power outage, it is necessary to constantly ensure the supply of a drinking water, if this requirement would not be met, it could cause of deterioration of hygiene and health of the population. To be able to convey drinking water during a blackout, it is mandatory to have a backup power supply. The state of the current water treatment plants in the Czech Republic is that they are using diesel generators as backup power supply, which causes air pollution. There are other options of power supply that can be used, such as renewable energy sources. By using a multi-criteria analysis method, renewable energy sources were analyzed for a water treatment plant in the selected region. Based on the results, it seems that the most suitable choice is a small hydro power plant at the entry points of water treatment plant. Other possibilities of renewable energy sources that may be suitable for a water treatment plant and the usage of a multi-criteria analysis method for a water treatment plant in other countries are also discussed.

The article concerns the energy security of a wastewater treatment process caused by unforeseen situations related to the risk of electrical power outages. In this case, renewable energy sources based on distributed generation power systems can solve this problem in each wastewater treatment plant. The article highlights e related challenges and proposes the direction of solutions in this regard based on Czech conditions. The first part of the paper deals with the consequences of long-term outage of wastewater treatment plants on the population and the environment. There are several solutions presented for blackout conditions, and model calculations are made based on data from a Czech wastewater treatment plant. Diesel engine-generators, biogas as a cogeneration source of heat and electricity, solar panels with storage systems and combined biogas and solar systems were considered as approaches to provide energy autonomy during a blackout in a wastewater treatment plant. Special attention was paid to a combination of CHP units with solar panels and batteries. The results were evaluated for three different locations for this combination. It was concluded that biogas combustion in the CHP unit was the most profitable option, allowing the production of electricity independently of the grid for its own consumption and possibly for other operations. The last part of the paper deals with the transition to island operation, which must occur during a blackout. This transition is more difficult for both solar panels and cogeneration units if they were to supply electricity to the grid before a blackout. The transition to energy island operation could be ensured by frequency relay and processor devices to control the circuit breaker. Then, to maintain island operation, it would be necessary to have an automatic load shedding/application system.

This article is focused on fault distance measuring with feeder protection relay REF630 from ABB and its function fault locator. This function provides impedance-based fault location. For measuring was used laboratory at Faculty of Electrical Engineering and Computer Science where is laboratory stand with inbuilt REF630 and fault module and where is also available module of transmission network. With those modules there were measured fault distance in case of phase-to-phase fault and phase-to-earth fault for various values of fault resistance. Parameters of typical 11 kV distribution network was set up in protection relay by ABB software PCM600. In case of phase-to-phase fault measured distance corresponded with parameters of model. However, in case of phase-to-earth fault measured fault distance was more than two times lower than our model. Measurement was repeated with parameters of zero sequence reactance equal to positive sequence rectance. Next results corresponded to our model parameters. All results confirmed assumption that higher fault resistance causes lower accuracy of calculated fault distance.

The article focuses on the ship’s electrical connection to the port, which appears to be an important technological element that will reduce air pollution in ports. Ports therefore install facilities that allow mooring ships to connect to the port distribution network. By 2025, this will be mandatory for all ports in Europe. That is why Shore Connection technology is experiencing a huge boom. All this means that in the future all ships staying in the port will have to be able to connect to the port and then power all their electrical appliances from the onshore distribution network. The ships will have to shut down their generators as soon as possible so that they no longer burn fossil fuels, which cause significant air pollution. Because ships near the port have to burn more expensive, greener fuels, it is often economically advantageous for them to connect to port distribution network. It is often cheaper for ships to buy electricity from the grid than to produce it with their own generators. Shore Connection must therefore be considered in the production of new ships, but this function is also being added on a large scale to already manufactured ships. This article discusses the most important devices that must be newly installed to connect to the port. The procedure for connecting a ship to a port is explained using an example of a Shore Connection solution supplied by ABB.

Ship-to-shore connection is an important technological element that reduces air pollution in ports. Therefore, ports install facilities that allow mooring ships to connect to the port distribution network. By 2025, this will be mandatory for all ports in Europe. This can be a challenging task in most ports due to the different frequency of the network and ship frequency. This problem can be solved by the use of grid-forming static frequency converters. This solution also brings some other advantages: The ship is not threatened by high shore short-circuit currents, and the port distribution network is not affected by the character of the ship load. However, frequency converter software must include a droop control algorithm to ensure that voltage deviations do not exceed the allowed limits during transients. Typical frequency converters used for shore connection are those developed as static frequency converters (SFCs). However, those converters were not developed for large power outputs, which are needed to power large vessels, such as ferries or cruise ships. This paper proposes motor drives that were modified to operate as SFCs. This approach has quite a lot of advantages which are described in this article. This paper describes both a standard shore connection system without a frequency converter and a solution that includes static frequency converters. The paper then focusses on voltage deviation estimations during connection/disconnection of large load (ferry or cruise ship) to static frequency converters. In this work, a high-voltage shore connection (HVSC) simulation model is developed, including a frequency converter, a shoreside transformer, medium-voltage (MV) connection cables, and a power system of the ship, to analyze in detail the behavior of the system in the case of connection or disconnection of the ship load. The model was made in DIgSILENT PowerFactory for the case of a commercial port in southern France. The model gives credible estimations of voltage drops/surges during transient and steady states.

A power outage of the distribution network could cause large economic losses and safety hazards for industrial companies. Therefore, many industrial companies have a backup power source. Nevertheless, without automatic transition between grid-connected and islanded modes, there will be some time of outage of all consumers. In this article, calculations of the system average interruption duration index (SAIDI) were done and how it changes when automatic transition will be available. The low voltage and medium voltage SAIDI index values for the Czech largest distribution network operator were used as basic values for the calculations. It was calculated that the SAIDI index will improve from 307 min/year to 32 min/year with CHP as the hot reserve at a low voltage level and from 331 min/year to 35 min/year at a medium voltage level. It means a huge improvement in the reliability of the electric power supply. Automatic transition systems are especially worthwhile for companies and plants for whom interruption of production is very costly or a safety hazard.