Wojciech Kostowski, Aleksandra Starzak, Krzysztof Pajączek, Piotr Niedzielski, Jacek Kalina, Andrzej Jedynak, Adam Przybył, Sylwia Rusek
Potential of waste heat utilisation in selected gas compressor stations
Presented is a waste heat recovery potential in three natural gas compressor stations (CS). Waste thermal power profiles have been built basing on the available measurement and nominal data. Then the demand profiles have been determined for 3 potential groups of consumers: CS stations in-house demand, space heating demand from municipal consumers and a hypothetic demand from industrial consumers. Balances have been set in a ‘8760 h/year’ layout. The identified recoverable potential of the 1–3 CSs exceeds 300 000 GJ and the highest recovery rate of 65% can be achieved at the CS#2 in case when municipal consumers are considered. The consumers’ demand coverage ratio ranges from 35% to 83%, which results from a non-continuous waste heat generation. Therefore, further research is aimed at the waste heat thermal storage.
Keywords: waste heat, gas compressor stations, characteristics of the waste heat generation, thermal storage
Julian Wiatr
Groundings in low voltage power grids
Groundings in low voltage power grids are a very important element of protection against electric shocks. Requirements in this area were defined in the N SEP-E 001 standard Low voltage power grids. Electric shock protection. But these requirements are very often incorrectly interpreted as a result of application of simplifying assumptions.
Keywords: low voltage power grids, groundings, N SEP-E 001 standard Low voltage power grids. Electric shock protection
Waldemar Dołęga
Operation of electrical power substations in energy enterprises
Described are issues concerning operation of electrical power substations in energy enterprises. Discussed is the importance of proper substation operation for its correct work. Presented are documents containing requirements and recommendations regarding operation of electrical power substations. Shown is technical and legal documantation of such substations with special attention paid to operational and service documentations. Discussed are selected issues connected with visual examination, technical inspections, assesment of technical condition and also maintenance and repairs of a substation itself and of an equipment and installations mounted inside it.
Keywords: electrical power substation, operation, energy enterprise
Krzysztof Billewicz
Energy generation and system services – possible consequences of moving away from coal
Debate article
Following problems are discussed: energy generation and system services, overproduction of solar energy, the level of a distribution system, changes in tariffs structure, electric energy storage, storage and tariffs, purposefulness of energy storage application and benefits for an investor. Together with decommissioning of big conventional power plants there will also change the paradigm of electric energy generation and transmission. The redesign of transmission networks – and probably of the distribution ones as well – will become necessary.
Keywords: electric energy generation, solar energy overproduction, electric energy storage
Stefan Gierlotka
Influence of temperature and relative humidity on the impedance of a human body
Susceptibility of a human to the impact of a shock current depends on the value of the human body impedance in the moment of shock. The cause increasing probability of occurrence of an electrocution dangerous effects are specific environmental conditions. Presented is adaptation of the earlier research on changes in a human's body impedance dependent on a climate determined with the use of a catathermometric method to the more useful dependence on temperature and relative humidity of the environment.
Keywords: shock current, value of a human's body impedance in the moment of electric shock, environmental conditions