Glossary of the terms and issues relating to the electrical power engineering, Part 3
In the previous parts (1, 2) of our glossary, we started describing the most important terms in the field of the electrical power engineering we deal with at Eltel Networks in Poland. Today, we present part three of the electricity glossary including, but not limited to, the types of electricity consumers, the term of RES, distribution and transmission system operators and the most frequently used types of power cables. Have a nice reading.
Electricity trading – business activity involving wholesale or retail trade of electricity.
DSO area – a power network owned by the distribution system operator (DSO) in the area defined in the DSO’s electricity distribution concession, the operation of which is the DSO’s responsibility.
Consumer – anyone who receives or draws electricity under a contract concluded with a power company.
Household electricity consumer – a final consumer who purchases electricity exclusively for household consumption.
Final consumer – a consumer that purchases electricity for his own use; the electricity purchased to be used for the purpose of generation, transmission or distribution is not considered as electricity for own use.
Disconnection from the network – permanent separation of the equipment, installation or network of an entity connected to the distribution network, including but not limited to permanent dismantling of the connection elements.
Renewable Energy Source (RES) – renewable non-fossil energy sources, including wind energy, solar energy, aerothermal energy, geothermal energy, hydrothermal energy, hydropower, wave energy, currents and tides, energy produced from solid biofuels, biogas and liquid biofuels.
Read more about renewable energy sources in our article Electrical power engineering in the face of the climate crisis
Power plant constraints – limitations resulting from the technical working conditions of generation units.
Network restrictions – maximally permissible or minimally required power generation at a given node or in a given area, or maximum permissible power transmission through a given network section, including for inter-system exchange, taking into account the current operating conditions of the National Power Grid.
Surge protection device (lightning arrester, surge arrester) – a device that protects electrical equipment against hazards such as lightning overvoltages, limiting the duration and frequency of the following current. Overvoltages can occur when, for example, switching on or off an unloaded overhead line or in a lightning strike. They may damage the insulation and other network components. Since lightning arresters are relatively expensive devices, they are only used to protect important network components such as transformers or generators.
Operator – a transmission system operator or a distribution system operator.
Distribution System Operator (DSO) – a power company, which distributes electricity and is responsible for the network traffic in the distribution system, on-going and long-term operational safety of the system, operation, maintenance, repairs and necessary extensions of the distribution network, including connections to other power systems.
Transmission System Operator (TSO) – a power company, which distributes electricity and is responsible for the network traffic in the distribution system, on-going and long-term operational safety of the system, operation, maintenance, repairs and necessary extensions of the distribution network, including connections to other power systems.
Entity applying for grid connection (entity connected to the grid) – an entity applying for connection of its equipment, installations or power network to the grid (an entity whose equipment, installations and networks are connected to the power grid).
Line manager – an employee authorized in writing to issue work instructions by the power plant equipment operator, holding a valid certificate of competence for the supervisory position.
Electric current – an organized movement of electrical charges (electrons).
Alternating current (AC) – a characteristic case of periodically alternating current in which instantaneous values change in a repetitive, periodic manner at a specified frequency.
Variable current – an electric current for which the intensity changes in time in any way.
Short-circuit current – measured in amperes, the current flowing through the system due to damage to the insulation of conductors, accessories or equipment.
Switching programs – procedures and activities relating to switching operations, voltage testing, creation of transitional arrangements and including new facilities into the power system, as well as after a long shutdowns due to modernization or conversion.
Power company – an entity whose business activity is the generation, transmission, distribution or trading of energy.
Trading company – a company whose business activity is wholesale or retail trade of electricity, irrespective of any other activities.
Unplanned interruption in the supply of electricity – an interruption due to a failure to the electricity grid, the duration of which is counted from the moment when the power company that transmits and distributes electricity receives information about its occurrence until the resumption of the supply of electricity.
Planned interruption in the supply of electricity – interruption resulting from the grid operating and maintenance program. The duration of this interruption is counted from the moment of opening the switch until the resumption of the supply of electricity.
Transmission – transport of electricity – transmission/transport of electricity through the transmission networks for the purpose of supplying it to the distribution networks and final consumers connected to the transmission networks, excluding the sales of electricity.
Aluminium Conductor Steel Reinforced (ACSR) cable – in Poland known as AFL cables (steel core aluminium strands), commonly used in all types of overhead lines. The core is made of galvanized steel wires, additionally coated with grease, or aluminized steel wires, while the conducting layer is made of AL1 aluminium. Due to the proper aluminium/steel cross-section ratio, the required electrical and mechanical properties of the wires are achieved. The permitted long-term operating temperature of the cable is 80°C.
Phase conductor – a live conductor that is under phase voltage during use. Its function is to conduct electricity in the power network. In a three-phase network, the conductor wires are marked L1, L2 and L3, respectively. The conductors in overhead power lines consist of a layer conducting electric current, made of aluminium or aluminium alloy wires, and a core, which is usually a steel wire, providing adequate mechanical strength of the entire conductor.
Want to learn more about conductors? Read our article Types of supporting structures for power lines
High Temperature Low Sag (HTLS) cable – suitable for use at elevated temperatures and characterized by low sags. The permitted operating temperature of conventional phase conductors usually does not exceed 80°C, and it is one of the basic parameters that determine the permitted current load of a particular overhead line. If it is necessary to increase the current-carrying capacity of the existing line, the cable can be replaced with one that is suitable for higher temperatures, i.e. HTLS. In addition, some types have a special core, made of, for example, carbon and glass fibres (ACCC), a composite material comprising aluminium oxide fibres (ACCR) or carbon fibres (ACFR).
Ground wire – a conductor that does not have voltage during normal operation. It is designed to protect the entire perimeter system from atmospheric discharges. It is grounded using the supporting structure (tower).
Optical ground wire (OPGW) – a ground wire that uses optical fibres in stainless steel tubes, replacing ground wires in the high-voltage power lines. The function of OPGWs is to protect live conductors from atmospheric discharges and short circuits as well as data transmission. The outer layer (one or two) consists of aluminium alloy wires or aluminium-coated steel wires that ensure the required mechanical strength and conductivity under the appropriate short-circuit conditions.
Connection – a section or element of the network used to connect the entity’s equipment, installations or networks, with the required connection power, to the rest of the network of the power company providing the transmission or distribution service to the entity.
Point of Electricity Supply – the point where the retail traffic participant (RTP) is connected to the distribution network outside the area of the Balancing Market, comprising one or more physical points of grid connection for which the trade balancing process is in place.
Point of Electricity Consumption – the point at which energy products (energy, transmission services, power, etc.) are metered by (periodic or hourly) measurement data recording devices. This is the smallest unit for which supplies are balanced and for which the seller may change.
Summary of the terms used in the electrical power engineering, Part 3
Want to find out more about what a high-voltage network, a transmission network or an inter-system exchange is? If so, please use part four of our glossary of the terms used in the electrical power engineering!
Author: Piotr Wyrzykowski