Dear customers,

We have prepared for you a brief review of power engineering terms used within the company Stredoslovenská energetika, a.s.. After clicking on the alphabet list an explanation of the particular expression will be displayed.

Example: You do not know what the abbreviation OK means? Click on the letter O and the alphabet list of expressions beginning with the letter O will be displayed. Then find the abbreviation OK and its description.

A  B  C   D  E  F   G  H  K  L  M  N  O  P  R  S  T  U  V 

If you miss any expression from the sphere of power engineering in our dictionary, do not hesitate and write us to the E-mail address: marketing@sse.sk.

Looking forward to your suggestions and comments.

A

Active electric energy

• "Visible" component of electric energy, which is changed into another kind of energy (kinetic, thermal, light energy, etc.) through the transition into electrical appliance.

Active power

• From the point of view of physics, active power is the one, which is possible to replace with another kind of energy suitable for terminal use, which can be mechanical, chemical, light, sound and heat energies.
  P = U . I . cos ? = Umax . Imax . cos ? / 2
  When compounding current and power factor we get active power, which is in a phase with voltage.
  Active power is expressed in kilowatts (kW).

Active work

• Active work is a basic parameter for the measurement of the power consumed. It is expressed in kilowatt-hours (kWh).

Adapter (of accessories)

• Portable accessories designed as an inseparable unit containing one plug-type part and one or several socket parts.

Adapter - multiple

• Adapter, which allows for paralel connection of more than one plug into all socket parts of the adapter.

Agreed 1/4h maximum

• Value of a quarter-of-an-hour electric output (maximum output taken during 15 minutes) agreed in the load profile, in SSE at customers with the so-called odd-numbered tariffs A1, B1, B3 and their derived tariffs A1a, A1b, A1c, A1d and B1a. The 1/4 h maximum agreed with these customers is checked through metering for 24 hours a day Monday to Sunday for the sake of invoicing.
  Contractual period of validity of the agreed 1/4 h maximum in customers in these tariffs is one month. Customer may change the value of the agreed 1/4 h maximum within 10 days prior to the beginning of the particular month.
  The agreed 1/4 h maximum is invoiced in the full height also in case that customer has not taken the whole agreed maximum. An increased price stipulated in the particular tariff in the Price List for electric energy is invoiced for exceeding the agreed 1/4 h maximum of power output. 

Air-operated contactor

• Contactor, in which power for connection or disconnection of the main contacts is provided by an apparatus using compressed air, without the use of electric means.

Apparent power

• Apparent power in circuits and facilities of alternative current is defined as a composition of effective value of voltages and current. In symmetrical multi-phase systems this conjunction is multiplied by the number of phases.
  S = U . I = Umax . Imax / 2
  Apparent power is expressed in kilovoltampers (kVA).

Apparent work

• Apparent work is a fictitious parameter, which is expressed in kVAh.

Auxilliary supply

• It is an electric power, invoiced according to the particular tariff from the auxilliary output and number of days of auxilliary supply as follows:
  Upon agreed output as a difference between the auxilliary output and the agreed output.
  Upon metered output as a difference between the auxilliary output and the metered output currently, while the difference must be higher than 0.
  Upon overrunning the contractual output in an auxilliary supply (technical maximum, increased by a reserve capacity), the supplier charges a price surcharge of 1,000,- SKK for every exceeded kW.

Average price

• The share of the sum of all particular charged sums in a concrete case of take-off for a certain time period (for example one year) and electric work (kWh) supplied in the same time period.

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B

Blocking of appliances

• Blocking of appliances is a technical measure preventing from switching electrical appliances on when the high tariff is in force. It is used upon electric heating systems and hot-water boilers. By means of preventing from switching these electrical appliances on, on one side, it compensates for the load of power system (in order to use electricity more effectively), on the other side, it saves costs of customers, since in the time of the high tariff electricity is more expensive.

Built-in switch

• Switch to be built-in into an appliance or onto an appliance, which can be tested independently.

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C

A category customer

• Customers connected to the network of a very high voltage (vhv)

B category customer

• Customers connected to the network of high voltage (hv)

C category customer

• Customers connected to the network of low voltage (lv)

D category customer

• Customer, the electric take-off facility of whom is connected to a public distribution of electricity of low voltage and the power consumption of whom serves only for the satisfaction of personal needs only (also for chalets, garages, gardens, etc., if the consumption does not serve undertaking).

Circuit-breaker

• A kind of protection of electrical circuits from overloading and short circuit. It is a self-operated circuit-breaker, which disconnects circuits feeding upon voltage increase over the certain limit value, or upon short circuit in a protected circuit. Dependability of the trip time on current size flowing through the circuit-breaker represents tripping characteristics of the circuit-breaker. Circuit-breakers are used as elementary protection from overloading and short circuit.

Clearing cycle

• Period, for which the customer was invoiced for power supply as a comparison of advance payments and the price of really supplied electric energy. Clearing cycle lasts normally for half a year (small-scale consumption) or for a month (large-scale consumption), but after an agreement it can last also for quarter of a year, or a year.

Connecting facility of an appliance

• Facilities allowing for aimed connection and disconnection of a cord of appliance or other facility composed of a socket and a connector.

Connector (of a connecting facility of an appliance)

• Part of a connecting facility of an appliance, which is integrated or built-in in an appliance or facility, or is fixed for attachment to them.

Controlled customer

• Power consumer, natural or legal entity, which consumes electricity based on a contract on power supply from the supplier operating the distribution system. It is the opposite of the eligible customer, who must have concluded a contract on power distribution for electricity take-off.

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D

DDZ _ Daily load profile

• The graph depicts the course of output loading of the electrical power system or its part during the day (24 hours)

• BASIC PARAMETERS OF DDZ:
• Pmax _ maximum output
• Pmin _ minimum output
• Ps _ average output
• tau _ time of utilization  of installed (maximum) output
• z _ load factor

Distributing system

• System of interconnected lines and electric stations serving for distribution within the Slovak Republic.

Dispatching

• Dispatching controls the operation of transmission system and ensures power balance between sources and electricity consumption.

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E

EEM

• Elektroenergetické montáže a.s. _ assembly operations, subsidiary corporation of SSE, a.s. providing renewal and development of power engineering facilities, which supply SSE, a.s. customers with electric energy.

Electric station

• Element of the electricity system, serving for the transformation, switching operation or modification of parameters of transmitted electric energy. Electric stations are devided into transformer stations (transformation into another voltage level), converter substations (change of alternative into direct current) and switching stations (safety and controlling facilities).

Electric energy production

• Process upon which electric energy is reached from a non_refined form of energy (coal, crude oil, water, ...).

Electricity system

• Set of elements (electric stations, power plants, power transmission lines, distributors, service lines), serving for the production, transmission, distribution and consumption of electric energy.

Electropneumatic contactor

• Contactor, in which power for connection and disconnection of the main contacts is provided by an apparatus using compressed air controlled by electrically operated valves.

Eligible customer

• Electricity purchaser, who is authorized based on legislation to conclude a contract on power supply and take_off with any supplier.

E_line

• In_plant periodic of the stock company Stredoslovenská energetika, a.s.

EU directive on market liberalization

• The directive has been designed for the member countries of the EU. It defines basic rules of internal market with electric energy. European Parliament in Brussels approved of it on December 19, 1996.

External wire

• Any cable, flexible cable or cord, wire core or wire, a part of which is situated on the external part of accessories.

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G

Green energy

• The term designating the supplied electric energy, which has been produced using alternative sources (small hydro power plants, solar energy, wind_power,...). Technically, it is not possible to ensure that just this part of electricity was supplied to the selected customer, that is why such supply is as a rule ensured in the way that the supplier sells green energy only in an amount, which equals to its purchase from such sources.

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H

HDO

• Centralized telecontrol of loads (HDO) allows SSE a.s. to transmit commands for switching tariffs at the electrometer to customers parallely with power supply, and to control the blocked direct heating and accumulation appliances using standard distribution networks. Demand for electric energy is in specified time periods (peak and high tariffs) higher, that is why appliances with high input power and those ones the operation of which is not inevitable (mostly electric heating), are disconnected within these periods by means of HDO.

Heat pump

• Function of heat pump is known by everybody, who owns for example a fridge or a freezer. The fridge removes heat from its internal area (=cools down) and it supplies it via cooling circuit into the external part of the facility, where heat removed from foodstuffs is released again.
  Heat pump (hereinafter referred to as HP) operates similarly as a fridge, with one exception that it does not remove heat from foodstuffs but it draws the so_called low_potential heat from external environment _ from air, ground, or water). Heat, which is refused in a fridge, is a cheap and very much wantable energy in a HP, which we use for heating and heating_up of utility water.

High tariff (HT)

• High tariff is a time zone, which in case of a two_rate tariff represents time zones of the high loading of electrical power system (high demand for electric energy); in case of a three_rate tariff _ middle loading of electrical power system (increased demand for electric energy). Price for the high tariff is in a concrete tariff always higher than the price of the low tariff and lower than the price for peak tariff (if the given tariff contains it).

House connection

• Line wire branching away from the supply network into the supply facility of the customer.

HV network

• High voltage network _ distribution network with the phase voltage from 1 kV to 52 kV. From this voltage level customers with _B_ tariffs are fed within SSE. Also supply points fed through a direct LV outlet from HV/LV transformer station are ranked into B category.

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I

Integrated wire

• Wire, which is situated in an accessory or is used for permanent interconnection of terminals or accessories__connections.

Internal wire

• Any cable, flexible cable, cord or wire, all situated in an appliance or facility, which, however, is neither external  nor integrated wire of accessories.

IT

• Information technologies

Installed Power Capacity

• Installed Power Capacity of the supply point equals to a sum of values of nominal outputs of electrical appliances of the customer connected to the grid.

Interconnection adapter

• Facility which allows for aimed connection and disconnection of an appliance or facility from flexible cable leading to another appliance or facility.

Integrated switch

• Switch, the function of which depends on its correct assembly and attachment to the appliance; It can be tested only in combination with the particular parts of an appliance.

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K

Kilowatt_hour (kWh)

• Unit of consumption of active electric energy. It is a composition of active output and time.
  1 kilowatt_hour is an amount of electricity consumed by for example :
  100 W bulb for 10 hours of operation,
  direct heating electric boiler with the output of 15 kW per 4 minutes,
  accumulation stove with the output of 3 kW per 20 minutes.

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L

Liberalization of market with electricity

• It means removal of regulatory measures and thus also an opportunity to select power supplier on one side and to create prices according to the market supply and demand relation on the other. This is manifested in the practice mostly by the removal of the state monopoly for administrative price determination. It need not necessarily mean cancellation of state price control _ mostly in the transition period.

Load control _ management

• Contractual provisions concerning accomodation to the power demand of electricity supplier. Power demand is reduced during certain time periods (e.g. period of a large load _ the zone of force of a peak or a high tariff), which are fixed by the electrical distribution or production plant. This can be a result of a partial or complete power disconnection from electrical distribution or production plant, or of an intentional reduction of the customer rationally utilizing electric energy.

Low tariff (LT)

• Low tariff is a time zone, when loading of the power grid is lower. During this period costs for production and transmission of electricity are usually lower. Power engineering companies therefore motivate consumption at this period by a lower price. Since the character of electricity consumption is changing during the year and during the day as well, the time zone, when customer pays lower price, can be changed depending on the tariff.

LV network

• Low voltage network _ distribution network with the phase voltage up to 1 kV. In the conditions of Slovakia the voltage level of 400 V for 3_phase current (phase voltage) is used as a standard, which represents voltage towards the ground _ 230 V. This system used to be known as 220/380 V.
  From this voltage level both undertakers (category _C_) and households (category _D_) are fed; maximum current value of the main circuit_breaker is 160A.

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M

Metrology

• Verification and calibration of electrometers, metering transformers, etc. for all participants in the market with electricity.
  Metrológia EV, spol. s r.o., as 100% subsidiary corporation of SSE, a.s. offers metrology services in accredited metrology laboratories (AML) in Žilina and in Banská Bystrica for electrometers, water_gauges, heat gauges and calibration of electric quantities.

MIP Price List

• Price List of minor installation works, which specifies costs settlement for services connected with electricity sale, which are not included in electricity price.

MVE

• Minor hydro power stations _ source of electric energy belonging into the group of minor sources of energy. Here belong sources (generators) with an installed power capacity up to 10MW (also cogenerating units, wind_power plants, solar generators, etc.), which may (parallel operation), but also need not be connected to the  distributing grid of SSE, a.s. (Island operation).

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O

OK

• Contact Office - a place of personal contact for the satisfaction of matters of contractual relation of a customer with SSE, a.s.

Output

• Output reflects an instant size of electricity being taken; from the physical point of view it is a composition of voltage (voltage level) and transient current. Within the framework of metering of output we know the so_called quarter_of_an_hour maximum (maximum output consumed during 15 minutes) and the technical maximum.
  1/4h maximum may be agreed on by the customer and SSE (tariffs A1, B1, B3, overrunning is charged subject to the Price List), or will only be metered (tariffs A2, B2, B4, B5, B10, B11, B12). Technical maximum is determined by the customer upon signing a contract and it can be changed as a rule only once a year.

Output _ maximum (CH _ Power maximum)

• The highest value (one_hour rating, half_an_hour rating, quarter_of_an_hour rating or n_minute rating, etc.) of customer´s output, which has been found within a certain period (year, quarter_of_a_year, month, week, day) at the place of handing over of the power supplied.
  Note: Maximum power found during the period of highest loading on a certain level of the grid is usually designated as _maximum loading_. Time period, during which the grid is loaded to the maximum, is called the period of _maximum loading_.

Output _ one_hour rating, half_an_hour rating, quarter_of_an_hour rating or n_minute rating, etc.

• Medium power claimed during the period of metering.

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P

Payment for power supplies from independent producers

• Price, charged by a distribution company, for electricity purchase from independent electricity producers. Independent producers (small hydro power plants, cogeneration units, wind_power plants, etc.) may, in case when it is allowed by the legislation, sell electric energy also directly to the selected partner after an agreement; however, he must settle the distribution fees in case of using the distribution netwrok.

Payment for the excession of power output

• Price list can define, in a concrete tariff containing payment for the output, the provision according to which a higher price is paid for the output, if the measured values exceeded the limit level agreed between the customer and the supplier. A similar payment may be fixed upon exceeding the agreed value of consumed work.

Period of utilization

• upon consumption the portion of labour consumed during a certain time period (year, month, day, etc.) and maximum output (technical date), expressed in hours;
  upon production (sources) of electric energy the portion of labour W [kWh] produced during a certain period of time (year, month, day, etc.) and maximum output of generator expressed in hours _ (Hydro Power Stations, cogeneration units, wind_power plants, etc.).

Phase

• Designation of a wire, bundle of conductors, outlet, winding or any other element of multi_phase alternative grid, which is under normal conditions under voltage.

Power engineering audit

• A survey of purposefulness and effectiveness of consumption of all forms of energy in the observed building and the proposal of realizable technical and organization measures to decrease productive as well as non_productive consumption of energy and their economic evaluation.
  Demandingness and range of the audit being administered depend also on the size of the building and complexity of production and take_off facilities. Audit can be devided into: basic audit _ preliminary; detailed (specific) audit

Power factor

• Parameter, objectifying active energy.
  Instant value of the power factor is a ratio of active output to the apparent output of the supply point:
  cos fí = Pč/S = P / U . I = 2 . P / (Umax . Imax) = [kW / kVA] = [kW / ?kW2 + kvar2] = <0...1>
  Mean value of the power factor is a ratio of active work to apparent work of the supply point. It objectifies the value of the power factor in a larger time span:
  cos fí = kWh / ?kWh1 + kvarh1
  contractual value subject to STN 33 3080 is 0.95 _ 1, unless agreed otherwise.

Power grid

• Set of individual interconnected electric stations, external and internal ones, and cable lines for the transmission and distribution of electric energy.

Power Plant

• Power engineering facility producing electric energy including facility for the production of electric energy, construction parts and all ancillary facilities.

Power supplies with prepayment

• We speak about a supply against advanced payment, when power take_off is carried out after inserting money (entering of the purchased numerical code or touching of a magnetic /chip card) into a special electrometer. This special way of clearance is known also under the designation _prepayment tariff_ or _tariff against advance payment_.

Power transmission

• Power transmission is a transmission of a volume of electric energy from the sources of electricity (power stations) into the spheres of consumption (large plants, distribution companies). We speak about transmission in connection with superior systems (220 kV, 400kV _ superior system, in Slovakia it is provided by SEPS, a.s.), on lower voltage levels we speak about power distribution.

Power transmission line

• Configuration of conductors, insulating materials and structures for the transmission of electric energy between two points of the power grid.

Prepayment, sometimes stated as advance payment

• The sum, which is necessary to pay for a certain time period (as a rule for a month, upon large_scale customers also once in 10 days). This sum depends on the take_off for a comparable period in the past.
  Note: In certain countries this basic sum can be composed of not only one but also of several price components (e.g. in Gemany of the price for electricity prepared to be delivered and the invoiced price).

Price for electric work

• This price component is a sum of payments for individual tariffs (low, high, peak). Number and time range of  tariffs (always totals 24 hours a day) are determined by the conditions of the particular tariff, while the total price of tariff is the composition of the measured consumption and price per 1 kWh.

Price for output

• Payment for an output is a composition of the value of monthly maximum (technical, 1/4hour agreed, measured or exceeded) and the price in compliance with the Price List.

Price regulation

• Upper and lower limit of price fixed by the state, which is lower or higher than the equilibrium price on the market in the form of the so_called price ceiling or price floor. In Slovakia URSO is responsible for regulation in the sphere of electric energy, gas, heat, water and sewage rates.

Protection

• A package of measures determined for tracing of troubles.
  PT _ peak tariff
  Tariff time zone, valid from Monday to Friday, is used for balancing the daily load profile in the times of excessive demand for electric energy.
  Zones of peak tariff validity are defined for individual months in the following way:
  a) October through March in the total length of duration of 7 hours daily,
  b) April through September in the total length of duration of 4 hours daily.
  Zones of peak tariff validity are determined and announced at least 10 days prior to their force at all customers concerned.

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R

RCS _ remote control switch

• Switch with a coil, which is remote_controlled by impulses and need not be permanently connected.

Reactive energy

• Electrical energy, which originates upon mutual activity of electric and magnetic fields. Reactive energy is not a generous form of energy, although it is used, for example, upon motor facilities running, or conversion into light energy in fluorescent tubes (upon utilizing this element of electric energy the consumption of active power is approx. 5 times lower).

Reactive power

• Output _ Q _ consumed for the creation of electric or magnetic fields in circuits of alternative current. It is an  imaginary parameter, which on the contrary to active power does not perform useful work.
  Q=U.I.sin?=Umax.Imax.sin?/2
  It is defined by the composition of effective values of voltages and reactive component of the alternative current component. It is expressed in kilovoltampers  _ reactant (kvar).

Reactive work

• Reactive work is a parameter, which objectifies the work of magnetic field. It is expressed in kVArh (reactance kilovoltamperhour)

Reserve output _ maximum, disposable output _ available power

• Limit value of the power, which is contractually guaranteed by the distribution plant after an agreement with the customer and which customer may claim in case of need beyond the technical maximum.

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S

Selenoid contactor

• Contactor, in which power for connection or disconnection of the main contacts is provided by a selenoid.

SEPS, a.s. _ Slovenská elektrizačná prenosová sústava, a.s.

• The mission of the company is to reliably operate the transmission system, provide dispatcher__s control of the system, its maintenance, renewal and development so that reliable and high quality power supply as well as parallel operation with the neighbouring systems subject to the recommendations of UCTE upon respecting non_discrimination and transparent principles of access to the networks with minimum influence on the environment, were secured.

Simple tariff _ single_tariff

• Tariff, which contains the same price for electric work during 24 hours, independently of the time of take_off. As a rule it contains also another component _ standing charge, which is charged for a month of take_off, independently of the amount of work taken.

Socket (of the connection facility of an appliance)

• Part of connection facility of an appliance, which is integrated into a string or is determined for the connection on a string connected to feeding.

Specification of the state of electricity in case of a small_scale consumption

• Based on the state of electrometer or a qualified estimate (in case of inaccessibility of a metering device) the supplier works out an invoice for electricity consumed. It is carried out as a rule once in 6 months.

Supply point

• Generally, it designates locality, from where electricity is taken. Ususally it is identical with the place, where electricity consumption is metered. Consumption of one customer can be metered simultaneously at several supply points.

Substitute inlet

• Another inlet hv or vhv line for the provision of a higher degree of power supply, which is charged according to the height of the ordered output.

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T

Tapped substation

• Electric station, which is connected with the electricity system only by means of a single line (branch wire).

Tariff

• Time zone, characterized by the size of electricity demand; By means of tariffs balance of DDZ is controlled. In the conditions of Slovakia distributuion companies use at present maximum 3 tariffs _ peak tariff (PT), high tariff (HT) and low tariff (NT), while in this order (when used in a concrete tariff) its price for kWh is decreasing.
  The term is connected also with the term tariff system. It is the system of tariffs used by a concrete supplier. Price list is then a survey of price components and provisions taken into account upon calculation of payments to be paid by each customer in the given tariff at the supply point.

Tariff

• Tariff system of payment for electricity, which serves for the determination of payment for electric energy. Tariffs are devided into groups of customers (e.g. tariffs for households, tariffs for large_scale consumption, etc.).

Tariff composed _ two_rate tariff, three_rate tariff

• Tariff, which contains two (HT, LT) or three (PT, HT, LT) tariffs. A sum of hours for these tariffs always equals 24 hours and their distribution during the day is defined by the conditions of the concrete tariff. Price of the tariff is the price for electric work, consumed in the time allowed for the given tariff.

Tariff blocked

• In the conditions of SSE it is a peak and high tariff. In connection with these concrete tariffs the determined electric appliances are disconnected (switched_off) (usually electric heating). It is blocked by means of an adjustment of electrical installation so that electric appliances are connected to a separate current circuit, which is connected to HDO receiver or switching clock using a contactor. Distribution company uses blocking for the control of loading and thus also effective power purchse.
  Size of the time zones may be fixed or variable. Size of the time zones and prices for kilowatt_hour may differ according to the season, however, it must always be kept subject to the Price List in force.

Tariff _ flat

• Tariff containing only one price, valid for the consumed electricity regardless of the consumed amount and output. Allocation of the tariff may be bound to the maximum input power of appliances at the supply point.
  This tariff is used only for supplies of a smaller size in cases, where installation of metering device would be uneconomical (e.g. public phone booths).

Tariff depending on the season _ seassonal tariff

• These tariffs are used upon large_scale consumption tariffs, where various prices are for individual tariffs depending on the season. As a rule, the price for the tariff is higher in winter period as a result of higher loading of electricity system.

Tariff for households

• Tariff, which is used exclusively for the category of households

Tariff has been designed for a small consumption

• Tariff (single_rate tariff or two_rate tariff), which is designed for supply points with lower consumption in the time of validity of the high tariff.

Tariff depending on the output and on the time of utilization

• Tariffs for large_scale customers, where there comes to the payment for the agreed 1/4h maximum, have the tariff alloted depending on the voltage level, height of 1/4 h maximum and its utilization per hour.

Tariff for auxilliary supplies

• Tariff, which is used by the customer operating his own source of power in situations, when in case of a fault (outage or repair of own source) he requires power supply.
  Auxilliary supplies (output reservation) must be agreed in advance and in such case the customer pays for 1 kW of the reserve output, agreed above the value of the technical maximum regardless if auxilliary supply was realized or not.  Price for 1 kW in case of auxilliary supply has been stipulated by the price list depending on the tariff.

TCC

• Telephone customer centre _ contact place of the company Stredoslovenská energetika, a.s. mostly for customers fed from the LV voltage level (low voltage _ 230/400 V).
  Telephone number: 0850 111 468 for a local call price in an unswitched network.

Technical maximum

• Technical maximum is the value of 1/4 h electric output, approved by both sides in the contract of purchase with the validity term of at least 12 months (if not agreed by the customer and the supplier otherwise).
  Only in exceptional cases (e.g seasonnal electricity take_offs) it is possible to change the value of technical maximum twice a year after a mutual agreement.
  Technical maximum is metered for the sake of inspection of its observation during the whole 24_hour_long period. If at the supply point comes to the overrun of the technical maximum above the agreed value the supplier charges an increased price for every overrun kW.

Terminal (of accessories)

• Part of accessories, to which a wire is connected, thus creating dismountable joint

Terminal plate

• Configuration composed of several connecting facilities of unlimited number, which are mutually isolated and placed on a common base or in a common base produced of insulation material. Individual connecting facilities may, but need not, have attaching means; connecting facilities are (independently or by groups) easily removable from adjoining apparatuses.

Transformer station

• Transformer station is a place of transmission or distribution network, where the voltage level is technically changed. Distribution transformer station ensures distribution of power into a certain area and as a rule it supplies one or more customers of a different level of importance.
  Transmission capacity
  This term designates physical transmission ability (in kW, or kVA) of the connecting facility or house connection, i.e. connection between distribution facilities of power plant distribution or production plant and the place of delivery at the customer.

Transmission system

• Part of distribution system, which serves for the transmission of electricity from power plants to distribution companies and large_scale customers, fed from 400 kV and 220kV voltage level (in Slovakia there are 5 customers like that). Transmission system in Slovakia is operated by SEPS, a.s. _ Slovenská elektrizačná prenosová sústava, a.s. (the Slovak electricity transmission system), which is also responsible for balancing production and consumption of electric energy between individual areas of transmission system.

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U

URSO

• Regulatory Office for Network Industries (URSO) originated in 2001 and is a body, the main mission of which is the state regulation within network industries _ upon production, purchase, transition and distribution of electricity, gas, heat, production and supply of potable water and sewage purification and removal. These are the industries, where there is missing a natural competition and exists a possibility of misusing the dominant position of producers and suppliers at the expense of customers.

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V

Variable costs

• Part of the total costs, which depends on the amount of electricity supplied to the facilities of the customer.

VHV network

• Very high voltage network _ network with the phase voltage over 52 kV. In the conditions of Slovakia, voltage levels of 110, 220 and 400 kV are used as a standard, abroad also 750 kV are used. From this voltage level with the voltage 110 kV are fed customers with _A_ tariffs within SSE.