- active power
means the real component of the apparent power at fundamental frequency, expressed in watts or multiples thereof such as kilowatts (‘kW’) or megawatts (‘MW’);
- alternator
means a device that converts mechanical energy into electrical energy by means of a rotating magnetic field;
- apparent power
means the product of voltage and current at fundamental frequency, and the square root of three in the case of three-phase systems, usually expressed in kilovolt-amperes (‘kVA’) or megavolt-amperes (‘MVA’);
- authorised certifier
means an entity that issues equipment certificates and power-generating module documents and whose accreditation is given by the national affiliate of the European cooperation for Accreditation (‘EA’), established in accordance with Regulation (EC) No 765/2008 of the European Parliament and of the Council;
- AVR
means the continuously acting automatic equipment controlling the terminal voltage of a synchronous power-generating module by comparing the actual terminal voltage with a reference value and controlling the output of an excitation control system;
- black start capability
means the capability of recovery of a power-generating module from a total shutdown through a dedicated auxiliary power source without any electrical energy supply external to the power-generating facility;
- connection agreement
means a contract between the relevant system operator and either the power-generating facility owner, demand facility owner, distribution system operator or HVDC system owner, which includes the relevant site and specific technical requirements for the power-generating facility, demand facility, distribution system, distribution system connection or HVDC system;
- connection point
means the interface at which the power-generating module, demand facility, distribution system or HVDC system is connected to a transmission system, offshore network, distribution system, including closed distribution systems, or HVDC system, as identified in the connection agreement;
- current
means the rate at which electric charge flows which is measured by the root-mean-square value of the positive sequence of the phase current at fundamental frequency;
- droop
means the ratio of a steady-state change of frequency to the resulting steady-state change in active power output, expressed in percentage terms.
- entity
means a regulatory authority, other national authority, system operator or other public or private body appointed under national law.
- EON
means a notification issued by the relevant system operator to a power-generating facility owner, demand facility owner, distribution system operator or HVDC system owner prior to energisation of its internal network;
- equipment certificate
means a document issued by an authorised certifier for equipment used by a power-generating module, demand unit, distribution system, demand facility or HVDC system.
- excitation control system
means a feedback control system that includes the synchronous machine and its excitation system;
- fast fault current
means a current injected by a power park module or HVDC system during and after a voltage deviation caused by an electrical fault with the aim of identifying a fault by network protection systems at the initial stage of the fault, supporting system voltage retention at a later stage of the fault and system voltage restoration after fault clearance;
- fault-ride-through
means the capability of electrical devices to be able to remain connected to the network and operate through periods of low voltage at the connection point caused by secured faults;
- FON
means a notification issued by the relevant system operator to a power-generating facility owner, demand facility owner, distribution system operator or HVDC system owner who complies with the relevant specifications and requirements, allowing them to operate respectively a power-generating module, demand facility, distribution system or HVDC system by using the grid connection;
- frequency
means the electric frequency of the system expressed in hertz that can be measured in all parts of the synchronous area under the assumption of a consistent value for the system in the time frame of seconds, with only minor differences between different measurement locations.
- frequency control
means the capability of a power-generating module or HVDC system to adjust its active power output in response to a measured deviation of system frequency from a setpoint, in order to maintain stable system frequency;
- frequency response deadband
means an interval used intentionally to make the frequency control unresponsive;
- frequency response insensitivity
means the inherent feature of the control system specified as the minimum magnitude of change in the frequency or input signal that results in a change of output power or output signal;
- FSM
means the operating mode of a power-generating module or HVDC system in which the active power output changes in response to a change in system frequency, in such a way that it assists with the recovery to target frequency;
- houseload operation
means the operation which ensures that power-generating facilities are able to continue to supply their in-house loads in the event of network failures resulting in power-generating modules being disconnected from the network and tripped onto their auxiliary supplies;
- inertia
means the property of a rotating rigid body, such as the rotor of an alternator, such that it maintains its state of uniform rotational motion and angular momentum unless an external torque is applied;
- installation document
means a simple structured document containing information about a type A power-generating module or a demand unit, with demand response connected below 1000 V, and confirming its compliance with the relevant requirements;
- instruction
means any command, within its authority, given by a system operator to a power-generating facility owner, demand facility owner, distribution system operator or HVDC system owner in order to perform an action;
- ION
means a notification issued by the relevant system operator to a power-generating facility owner, demand facility owner, distribution system operator or HVDC system owner which allows them to operate respectively a power-generating module, demand facility, distribution system or HVDC system by using the grid connection for a limited period of time and to initiate compliance tests to ensure compliance with the relevant specifications and requirements;
- island operation
means the independent operation of a whole network or part of a network that is isolated after being disconnected from the interconnected system, having at least one power-generating module or HVDC system supplying power to this network and controlling the frequency and voltage;
- LON
means a notification issued by the relevant system operator to a power-generating facility owner, demand facility owner, distribution system operator or HVDC system owner who had previously attained FON status but is temporarily subject to either a significant modification or loss of capability resulting in non-compliance with the relevant specifications and requirements.
- main generating plant
means one or more of the principal items of equipment required to convert the primary source of energy into electricity;
- minimum regulating level
means the minimum active power, as specified in the connection agreement or as agreed between the relevant system operator and the power-generating facility owner, down to which the power-generating module can control active power;
- minimum stable operating level
means the minimum active power, as specified in the connection agreement or as agreed between the relevant system operator and the power-generating facility owner, at which the power-generating module can be operated stably for an unlimited time;
- network
means a plant and apparatus connected together in order to transmit or distribute electricity;
- offshore grid connection system
means the complete interconnection between an offshore connection point and the onshore system at the onshore grid interconnection point;
- offshore power park module
means a power park module located offshore with an offshore connection point;
- onshore grid interconnection point
means the point at which the offshore grid connection system is connected to the onshore network of the relevant system operator;
- overexcitation limiter
means a control device within the AVR which prevents the rotor of an alternator from overloading by limiting the excitation current;
- PGMD
means a document provided by the power-generating facility owner to the relevant system operator for a type B or C power-generating module which confirms that the power-generating module's compliance with the technical criteria set out in this Regulation has been demonstrated and provides the necessary data and statements, including a statement of compliance;
- Pmax
means the maximum continuous active power which a power-generating module can produce, less any demand associated solely with facilitating the operation of that power-generating module and not fed into the network as specified in the connection agreement or as agreed between the relevant system operator and the power-generating facility owner;
- power factor
means the ratio of the absolute value of active power to apparent power;
- power-generating facility
means a facility that converts primary energy into electrical energy and which consists of one or more power-generating modules connected to a network at one or more connection points;
- power-generating facility owner
means a natural or legal entity owning a power-generating facility;
- power-generating module
means either a synchronous power-generating module or a power park module;
- PPM
means a unit or ensemble of units generating electricity, which is either non-synchronously connected to the network or connected through power electronics, and that also has a single connection point to a transmission system, distribution system including closed distribution system or HVDC system;
- PSS
means an additional functionality of the AVR of a synchronous power-generating module whose purpose is to damp power oscillations;
- pump-storage
means a hydro unit in which water can be raised by means of pumps and stored to be used for the generation of electrical energy;
- reactive power
means the imaginary component of the apparent power at fundamental frequency, usually expressed in kilovar (‘kVAr’) or megavar (‘MVAr’);
- relevant system operator
means the transmission system operator or distribution system operator to whose system a power-generating module, demand facility, distribution system or HVDC system is or will be connected;
- relevant TSO
means the TSO in whose control area a power-generating module, a demand facility, a distribution system or a HVDC system is or will be connected to the network at any voltage level;
- secured fault
means a fault which is successfully cleared according to the system operator's planning criteria;
- setpoint
means the target value for any parameter typically used in control schemes;
- slope
means the ratio of the change in voltage, based on reference 1 pu voltage, to a change in reactive power in-feed from zero to maximum reactive power, based on maximum reactive power;
- statement of compliance
means a document provided by the power-generating facility owner, demand facility owner, distribution system operator or HVDC system owner to the system operator stating the current status of compliance with the relevant specifications and requirements;
- stator
means the portion of a rotating machine which includes the stationary magnetic parts with their associated windings;
- steady-state stability
means the ability of a network or a synchronous power-generating module to revert and maintain stable operation following a minor disturbance;
- synchronous area
means an area covered by synchronously interconnected TSOs, such as the synchronous areas of Continental Europe, Great Britain, Ireland-Northern Ireland and Nordic and the power systems of Lithuania, Latvia and Estonia, together referred to as ‘Baltic’ which are part of a wider synchronous area;
- synchronous compensation operation
means the operation of an alternator without prime mover to regulate voltage dynamically by production or absorption of reactive power;
- synchronous power-generating module
means an indivisible set of installations which can generate electrical energy such that the frequency of the generated voltage, the generator speed and the frequency of network voltage are in a constant ratio and thus in synchronism;
- synthetic inertia
means the facility provided by a power park module or HVDC system to replace the effect of inertia of a synchronous power-generating module to a prescribed level of performance;
- underexcitation limiter
means a control device within the AVR, the purpose of which is to prevent the alternator from losing synchronism due to lack of excitation;
- voltage
means the difference in electrical potential between two points measured as the root-mean-square value of the positive sequence phase-to-phase voltages at fundamental frequency;