Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (Text with EEA relevance. )

PART I

GENERAL PROVISIONS

Article 1

Subject matter

For the purpose of safeguarding operational security, frequency quality and the efficient use of the interconnected system and resources, this Regulation lays down detailed guidelines on:

(a) requirements and principles concerning operational security;

(b) rules and responsibilities for the coordination and data exchange between TSOs, between TSOs and DSOs, and between TSOs or DSOs and SGUs, in operational planning and in close to real-time operation;

(c) rules for training and certification of system operator employees;

(d) requirements on outage coordination;

(e) requirements for scheduling between the TSOs' control areas; and

(f) rules aiming at the establishment of a Union framework for load-frequency control and reserves.

Article 2

Scope

The rules and requirements set out in this Regulation shall apply to the following SGUs:

(a) existing and new power generating modules that are, or would be, classified as type B, C and D in accordance with the criteria set out in Article 5 of Commission Regulation (EU) 2016/631 (¹);

(b) existing and new transmission-connected demand facilities;

(c) existing and new transmission-connected closed distribution systems;

(d) existing and new demand facilities, closed distribution systems and third parties if they provide demand response directly to the TSO in accordance with the criteria in Article 27 of Commission Regulation (EU) 2016/1388 (²);

(e) providers of redispatching of power generating modules or demand facilities by means of aggregation and providers of active power reserve in accordance with Title 8 of Part IV of this Regulation; and

(f) existing and new high voltage direct current (‘HVDC’) systems in accordance with the criteria in Article 3(1) of Commission Regulation (EU) 2016/1447 (³).

Article 3

Definitions

In addition, the following definitions shall apply:

(1) ‘operational security’ means the transmission system's capability to retain a normal state or to return to a normal state as soon as possible, and which is characterised by operational security limits;

(2) ‘constraint’ means a situation in which there is a need to prepare and activate a remedial action in order to respect operational security limits;

(3) ‘N-situation’ means the situation where no transmission system element is unavailable due to occurrence of a contingency;

(4) ‘contingency list’ means the list of contingencies to be simulated in order to test the compliance with the operational security limits;

(5) ‘normal state’ means a situation in which the system is within operational security limits in the N-situation and after the occurrence of any contingency from the contingency list, taking into account the effect of the available remedial actions;

(6) ‘frequency containment reserves’ or ‘FCR’ means the active power reserves available to contain system frequency after the occurrence of an imbalance;

(7) ‘frequency restoration reserves’ or ‘FRR’ means the active power reserves available to restore system frequency to the nominal frequency and, for a synchronous area consisting of more than one LFC area, to restore power balance to the scheduled value;

(8) ‘replacement reserves’ or ‘RR’ means the active power reserves available to restore or support the required level of FRR to be prepared for additional system imbalances, including generation reserves;

(9) ‘reserve provider’ means a legal entity with a legal or contractual obligation to supply FCR, FRR or RR from at least one reserve providing unit or reserve providing group;

(10) ‘reserve providing unit’ means a single or an aggregation of power generating modules and/or demand units connected to a common connection point fulfilling the requirements to provide FCR, FRR or RR;

(11) ‘reserve providing group’ means an aggregation of power generating modules, demand units and/or reserve providing units connected to more than one connection point fulfilling the requirements to provide FCR, FRR or RR;

(12) ‘load-frequency control area’ or ‘LFC area’ means a part of a synchronous area or an entire synchronous area, physically demarcated by points of measurement at interconnectors to other LFC areas, operated by one or more TSOs fulfilling the obligations of load-frequency control;

(13) ‘time to restore frequency’ means the maximum expected time after the occurrence of an instantaneous power imbalance smaller than or equal to the reference incident in which the system frequency returns to the frequency restoration range for synchronous areas with only one LFC area and in the case of synchronous areas with more than one LFC area, the maximum expected time after the occurrence of an instantaneous power imbalance of an LFC area within which the imbalance is compensated;

(14) ‘(N-1) criterion’ means the rule according to which the elements remaining in operation within a TSO's control area after occurrence of a contingency are capable of accommodating the new operational situation without violating operational security limits;

(15) ‘(N-1) situation’ means the situation in the transmission system in which one contingency from the contingency list occurred;

(16) ‘active power reserve’ means the balancing reserves available for maintaining the frequency;

(17) ‘alert state’ means the system state in which the system is within operational security limits, but a contingency from the contingency list has been detected and in case of its occurrence the available remedial actions are not sufficient to keep the normal state;

(18) ‘load-frequency control block’ or ‘LFC block’ means a part of a synchronous area or an entire synchronous area, physically demarcated by points of measurement at interconnectors to other LFC blocks, consisting of one or more LFC areas, operated by one or more TSOs fulfilling the obligations of load-frequency control;

(19) ‘area control error’ or ‘ACE’ means the sum of the power control error (‘ΔP’), that is the real-time difference between the measured actual real time power interchange value (‘P’) and the control program (‘P0’) of a specific LFC area or LFC block and the frequency control error (‘KΔf’), that is the product of the K-factor and the frequency deviation of that specific LFC area or LFC block, where the area control error equals ΔP+KΔf;

(20) ‘control program’ means a sequence of set-point values for the netted power interchange of a LFC area or LFC block over alternating current (‘AC’) interconnectors;

(21) ‘voltage control’ means the manual or automatic control actions at the generation node, at the end nodes of the AC lines or HVDC systems, on transformers, or other means, designed to maintain the set voltage level or the set value of reactive power;

(22) ‘blackout state’ means the system state in which the operation of part or all of the transmission system is terminated;

(23) ‘internal contingency’ means a contingency within the TSO's control area, including interconnectors;

(24) ‘external contingency’ means a contingency outside the TSO's control area and excluding interconnectors, with an influence factor higher than the contingency influence threshold;

(25) ‘influence factor’ means the numerical value used to quantify the greatest effect of the outage of a transmission system element located outside of the TSO's control area excluding interconnectors, in terms of a change in power flows or voltage caused by that outage, on any transmission system element. The higher is the value the greater the effect;

(26) ‘contingency influence threshold’ means a numerical limit value against which the influence factors are checked and the occurrence of a contingency located outside of the TSO's control area with an influence factor higher than the contingency influence threshold is considered to have a significant impact on the TSO's control area including interconnectors;

(27) ‘contingency analysis’ means a computer based simulation of contingencies from the contingency list;

(28) ‘critical fault clearing time’ means the maximum fault duration for which the transmission system retains stability of operation;

(29) ‘fault’ means all types of short-circuits (single-, double- and triple-phase, with and without earth contact), a broken conductor, interrupted circuit, or an intermittent connection, resulting in the permanent non-availability of the affected transmission system element;

(30) ‘transmission system element’ means any component of the transmission system;

(31) ‘disturbance’ means an unplanned event that may cause the transmission system to divert from the normal state;

(32) ‘dynamic stability’ is a common term including the rotor angle stability, frequency stability and voltage stability;

(33) ‘dynamic stability assessment’ means the operational security assessment in terms of dynamic stability;

(34) ‘frequency stability’ means the ability of the transmission system to maintain frequency stable in the N-situation and after being subjected to a disturbance;

(35) ‘voltage stability’ means the ability of a transmission system to maintain acceptable voltages at all nodes in the transmission system in the N-situation and after being subjected to a disturbance;

(36) ‘system state’ means the operational state of the transmission system in relation to the operational security limits which can be normal state, alert state, emergency state, blackout state and restoration state;

(37) ‘emergency state’ means the system state in which one or more operational security limits are violated;

(38) ‘restoration state’ means the system state in which the objective of all activities in the transmission system is to re-establish the system operation and maintain operational security after the blackout state or the emergency state;

(39) ‘exceptional contingency’ means the simultaneous occurrence of multiple contingencies with a common cause;

(40) ‘frequency deviation’ means the difference between the actual and the nominal frequency of the synchronous area which can be negative or positive;

(41) ‘system frequency’ means the electric frequency of the system that can be measured in all parts of the synchronous area under the assumption of a coherent value for the system in the timeframe of seconds, with only minor differences between different measurement locations;

(42) ‘frequency restoration process’ or ‘FRP’ means a process that aims at restoring frequency to the nominal frequency and, for synchronous areas consisting of more than one LFC area, a process that aims at restoring the power balance to the scheduled value;

(43) ‘frequency restoration control error’ or ‘FRCE’ means the control error for the FRP which is equal to the ACE of a LFC area or equal to the frequency deviation where the LFC area geographically corresponds to the synchronous area;

(44) ‘schedule’ means a reference set of values representing the generation, consumption or exchange of electricity for a given time period;

(45) ‘K-factor of an LFC area or LFC block’ means a value expressed in megawatts per hertz (‘MW/Hz’), which is as close as practical to, or greater than the sum of the auto-control of generation, self-regulation of load and of the contribution of frequency containment reserve relative to the maximum steady-state frequency deviation;

(46) ‘local state’ means the qualification of an alert, emergency or blackout state when there is no risk of extension of the consequences outside of the control area including interconnectors connected to this control area;

(47) ‘maximum steady-state frequency deviation’ means the maximum expected frequency deviation after the occurrence of an imbalance equal to or less than the reference incident at which the system frequency is designed to be stabilised;

(48) ‘observability area’ means a TSO's own transmission system and the relevant parts of distribution systems and neighbouring TSOs' transmission systems, on which the TSO implements real-time monitoring and modelling to maintain operational security in its control area including interconnectors;

(49) ‘neighbouring TSOs’ means the TSOs directly connected via at least one AC or DC interconnector;

(50) ‘operational security analysis’ means the entire scope of the computer based, manual and automatic activities performed in order to assess the operational security of the transmission system and to evaluate the remedial actions needed to maintain operational security;

(51) ‘operational security indicators’ means indicators used by TSOs to monitor the operational security in terms of system states as well as faults and disturbances influencing operational security;

(52) ‘operational security ranking’ means the ranking used by TSOs to monitor the operational security on the basis of the operational security indicators;

(53) ‘operational tests’ means the tests carried out by a TSO or DSO for maintenance, development of system operation practices and training and to acquire information on transmission system behaviour under abnormal system conditions and the tests carried out by significant grid users for similar purposes on their facilities;

(54) ‘ordinary contingency’ means the occurrence of a contingency of a single branch or injection;

(55) ‘out-of-range contingency’ means the simultaneous occurrence of multiple contingencies without a common cause, or a loss of power generating modules with a total loss of generation capacity exceeding the reference incident;

(56) ‘ramping rate’ means the rate of change of active power by a power generating module, demand facility or HVDC system;

(57) ‘reactive power reserve’ means the reactive power which is available for maintaining voltage;

(58) ‘reference incident’ means the maximum positive or negative power deviation occurring instantaneously between generation and demand in a synchronous area, considered in the FCR dimensioning;

(59) ‘rotor angle stability’ means the ability of synchronous machines to remain in synchronism under N-situation and after being subject to a disturbance;

(60) ‘security plan’ means the plan containing a risk assessment of critical TSO's assets to major physical- and cyber-threat scenarios with an assessment of the potential impacts;

(61) ‘stability limits’ means the permitted boundaries for the operation of the transmission system in terms of respecting the limits of voltage stability, rotor angle stability and frequency stability;

(62) ‘wide area state’ means the qualification of an alert state, emergency state or blackout state when there is a risk of propagation to the interconnected transmission systems;

(63) ‘system defence plan’ means the technical and organisational measures to be undertaken to prevent the propagation or deterioration of a disturbance in the transmission system, in order to avoid a wide area state disturbance and blackout state;

(64) ‘topology’ means the data concerning the connectivity of the different transmission system or distribution system elements in a substation and includes the electrical configuration and the position of circuit breakers and isolators;

(65) ‘transitory admissible overloads’ means the temporary overloads of transmission system elements which are allowed for a limited period and which do not cause physical damage to the transmission system elements as long as the defined duration and thresholds are respected;

(66) ‘virtual tie-line’ means an additional input of the controllers of the involved LFC areas that has the same effect as a measuring value of a physical interconnector and allows exchange of electric energy between the respective areas;

(67) ‘flexible alternating current transmission systems’ or ‘FACTS’ means equipment for the alternating current transmission of electric power, aiming at enhanced controllability and increased active power transfer capability;

(68) ‘adequacy’ means the ability of in-feeds into an area to meet the load in that area;

(69) ‘aggregated netted external schedule’ means a schedule representing the netted aggregation of all external TSO schedules and external commercial trade schedules between two scheduling areas or between a scheduling area and a group of other scheduling areas;

(70) ‘availability plan’ means the combination of all planned availability statuses of a relevant asset for a given time period;

(71) ‘availability status’ means the capability of a power generating module, grid element or demand facility to provide a service for a given time period, regardless of whether or not it is in operation;

(72) ‘close to real-time’ means the time lapse of not more than 15 minutes between the last intraday gate closure and real-time;

(73) ‘consumption schedule’ means a schedule representing the consumption of a demand facility or of a group of demand facilities;

(74) ‘ENTSO for Electricity operational planning data environment’ means the set of application programs and equipment developed in order to allow the storage, exchange and management of the data used for operational planning processes between TSOs;

(75) ‘external commercial trade schedule’ means a schedule representing the commercial exchange of electricity between market participants in different scheduling areas;

(76) ‘external TSO schedule’ means a schedule representing the exchange of electricity between TSOs in different scheduling areas;

(77) ‘forced outage’ means the unplanned removal from service of a relevant asset for any urgent reason that is not under the operational control of the operator of the concerned relevant asset;

(78) ‘generation schedule’ means a schedule representing the electricity generation of a power generating module or of a group of power generating modules;

(79) ‘internal commercial trade schedule’ means a schedule representing the commercial exchange of electricity within a scheduling area between different market participants;

(80) ‘internal relevant asset’ means a relevant asset which is part of a TSO's control area or a relevant asset located in a distribution system, including a closed distribution system, which is connected directly or indirectly to that TSO's control area;

(81) ‘netted area AC position’ means the netted aggregation of all AC external schedules of an area;

(82) ‘outage coordination region’ means a combination of control areas for which TSOs define procedures to monitor and where necessary coordinate the availability status of relevant assets in all time-frames;

(83) ‘relevant demand facility’ means a demand facility which participates in the outage coordination and the availability status of which influences cross-border operational security;

(84) ‘relevant asset’ means any relevant demand facility, relevant power generating module, or relevant grid element partaking in the outage coordination;

(85) ‘relevant grid element’ means any component of a transmission system, including interconnectors, or of a distribution system, including a closed distribution system, such as a single line, a single circuit, a single transformer, a single phase-shifting transformer, or a voltage compensation installation, which participates in the outage coordination and the availability status of which influences cross-border operational security;