Joint construction – concepts

Concept

Definition

Disconnector station

A station consisting of disconnectors. A disconnector is a medium or high-voltage switching device used to disconnect load from electric circuit at off-load condition. A disconnector creates a visible clearance between contacts.

Branch point

A point where a power line (overhead line) is divided into separate branches.

Overhead cable

A cable attached to a utility pole or other structure above the ground.

Distribution substation

A distribution substation is a transformer station where medium voltage is transformed into low voltage used by real-estate units.

Distribution cabinet

A distribution cabinet is a low-voltage substation designed to be installed above the ground.

Wire zone

A wire zone is an area of limited construction, formed by a wire zone clearance and border zones on both sides of the wire zone. Height restrictions for trees are in place in these zones.

The wire zone and border zones for high-voltage power lines are determined as follows:

- For a power line of 110 kV, the width of the wire zone is usually 26–30 metres.

 - For a power line of 220 kV, the width of the wire zone is usually 32–38 metres.

- For a power line of 400 kV, the width of the wire zone is usually 36–42 metres.

The width of the border zones is usually 10 metres on both sides of the line.

Cable (electrical)

A cable is a multipolar electric wire. Overhead line (electricity) An overhead line is an electric wire attached to utility poles above the ground. Open wire An open wire is an overhead line where each conductor is separately attached to an isolator or some other fastener.

Circuit breaker substation

A substation consisting of circuit breakers. A circuit breaker is a device used to disconnect load from electric circuit at on-load condition.

Medium-voltage wire

Definition of the Energy Authority: 1–70 kV electric wires are medium-voltage wires.

Compensation station

Equipment for regulating reactive power and network current, which can be used to reduce the voltage, power and energy losses occurring in wires and transformers.

Switching substation

A switching substation is a point in a high or medium-voltage distribution network, where it is possible to make different connections, centralise the transmission of electric current or distribute it to different lines. Thus, a switching substation is an electrical substation with no voltage transformation.

Line connection

A line connection means a power line built for an individual electricity consumption point or for one or several powerplants, by which a party or parties can be connected to the electricity network.

Earth conductor

A conductor that forms a conductive connection between a part of a system or equipment and the ground.

Metering substation

Equipment for measuring electricity.

Low-voltage wire

Definition of the Energy Authority: electric wires of 1 kV or less are

low-voltage wires.

Low-voltage substation

Equipment for connecting and wiring electric lines.

Low-voltage switch

Low-voltage operated switchgear for disconnecting load from electric circuit.

Route

A physical space either underground or in the air, such as an excavation or a geometric space defined by overhead lines, in which a power line or lines are placed. NB: A route is an independent

geometric entity – such as an excavation measured during cable installation. A route is not

related to other routes or power grid nodes such as electrical substations or distribution cabinets.

Thus, routes do not form a route network, and no route exists between two electrical substations.

Casing pipe

A pipe for protecting an electric wire or a telecommunication cable. A casing pipe in itself is a protective structure, but it can also be a part of other protective structures.

Protective structure

A structure located at construction sites for the physical protection or installation of electric and telecommunication wires. Such structures include casing pipes, cable channels, cable racks and cable troughs.

High-voltage wire

Definition of the Energy Authority: 110 kV–400 kV electric wires are high-voltage wires.

Electrical substation

An electrical substation is a point in a high or medium-voltage distribution network, where it is possible to transform voltage, make different connections, and centralise the transmission of electric current or distribute it to different lines.

Power line

A power line means an isolated entity formed by phase conductors and other conductors. A power line can contain spliced joints, provided that the technical qualities of the line are not altered in the joint.

NB: The conductors in an open wire attached to a utility pole are visible. The wire is air insulated.

Utility pole

A pole for attaching an above-ground power line.

Main switchboard

A main switchboard is the main distribution station of a building or structure. The power supply network of a building and consumer units are connected to the national grid through a main switchboard. The main switchboard always has main fuses, the main electricity meter (kilowatt-hour meter) and the main switch. In addition, the main switchboard can have individual fuses for the consumer unit outputs, a tariff switching module, socket outlets and components related to operation control/monitoring.

Concept

Definition

Campus distributor

A distribution station serving a specific geographic area.

Distributor

A cross-connection station where the conductor pairs or optical fibres of a telecommunications cable are connected

 to the conductor pairs or optical fibres of another telecommunications cable.

Joint (telecommunications)

An assembly designed to connect two or more telecommunications cables. NB: A telecommunications cable can split in the joint into two or more cables.

Conductor pair

A part of a circuit formed by two bunched conductors.

Cable well

A physical space with connected casing pipes, through which it is possible to

extend the cable network by blowing telecommunications cables into the casing pipes.

Cable route

A space either underground or in the air, in which a telecommunications cable is placed.

Coaxial cable

A coaxial cable is a transmission line that transmits a high-frequency electromagnetic field

from one place to another. The name of the coaxial cable comes from its structure: it consists

 of an inner conductor surrounded by a tubular conducting shield. Coaxial cables are most commonly used as antenna cables for televisions.

Copper cable

A telecommunications cable consisting of copper conductors. Fibre optic cable A telecommunications cable consisting of optical fibres.

Connection route

Signal transfer between two separation points, usually between the separation point of a building distributor and

 the separation point of a conductor pair in a telecommunications centre.

Main distributor

A distribution station serving a specific geographic area.

Casing pipe

A pipe for protecting a power line or a telecommunications cable, in which it is possible

 to install one or several electric wires or telecommunications cables. The casing is in itself a protective structure, but it can also be a part of other protective structures.

Protective structure

A structure located at construction sites for the physical protection or installation of electric and telecommunications lines. Such structures include casing pipes, cable channels, cable racks,

cable troughs and cable wells.

Building distributor

A distributor station serving a specific building.

Telecommunications cable

A cable with a uniform sheath, containing conductors or optical fibres made of copper or some other conductive material.

Telecommunications centre

A centre for the processing of telecommunication. Data centres and call centres are telecommunications centres.

Base station

A distribution station for connecting terminal devices to a data transmission network by radio.

Outdoor joint casing

A casing for extending, ending or branching a cable;

located outside (in a cable well, on a pole or underground).

Optical fibre

An optical fibre is a thin strand made of glass or plastic (e.g. acrylic resin) for the purpose of  conducting light.

Connection distance

A connection distance refers to the physical telecommunications connection between two nodes, such as two distribution stations. The connection distance determines the distribution station separation points between which signal transfer takes place. The concept of connection distance links the physical and logical networks to each other. NB: A connection route can be implemented through nodes with an existing connection distance.