Romania (Transelectrica/ANRE storage norm) ride-through requirements
Low-voltage ride-through, Frequency ride-through for Romania. Every breakpoint below is read from the code itself, and where a point was taken off a published figure rather than stated in the clause, the section under that chart says so — an envelope that stops where its published chart stops.
What is the low-voltage ride-through envelope for Romania (Transelectrica/ANRE storage norm)?
The plant must ride through for any voltage that stays on or above this envelope. The envelope holds 0 pu from t = 0 to 250 ms; then ramps linearly from 0 pu at 250 ms to 0.85 pu at 3 s; then 0.85 pu from 3 s, plotted to 60 min.
The clause states this boundary as a line; intermediate points are interpolated between its stated vertices. The envelope stops where the published chart stops; the code states no end time.
Applies to Category D electricity storage installations (RfG type D)
| From | To | Voltage | Between the points |
|---|---|---|---|
| 0 | 250 ms | 0 pu | Held flat |
| 250 ms | 3 s | 0 → 0.85 pu | Ramps linearly |
| 3 s | plotted to 60 min | 0.85 pu | Held flat |
The clause this came from
Normă tehnică privind cerinţele tehnice de racordare ... pentru instalaţiile de stocare a energiei electrice, aprobată prin Ordinul ANRE nr. 3/2023 din 18.01.2023 (Monitorul Oficial al României, Partea I, Nr. 53/19.I.2023; în vigoare 20.01.2023) — Art. 15 lit. a) pct. (ii), Fig. 4 + Tabelul 5 (IS de categoria D). The code defines a linear recovery ramp; the vertices are read from the clause and the chart draws the segment between them.
What is the frequency ride-through envelope for Romania (Transelectrica/ANRE storage norm)?
The plant must ride through between the upper and lower bands. The upper (over-frequency) band holds 51.5 Hz from t = 0 to 30 min; then 51 Hz from 30 min onward — the last band the envelope defines, with no stated end time. The lower (under-frequency) band holds 47.5 Hz from t = 0 to 30 min; then 49 Hz from 30 min onward — the last band the envelope defines, with no stated end time.
Every breakpoint is stated in the clause cited below.
Applies to Category D electricity storage installations (RfG type D)
Upper limit
| From | To | Frequency | Between the points |
|---|---|---|---|
| 0 | 30 min | 51.5 Hz | Held flat |
| 30 min | no stated end | 51 Hz | Held flat |
Lower limit
| From | To | Frequency | Between the points |
|---|---|---|---|
| 0 | 30 min | 47.5 Hz | Held flat |
| 30 min | no stated end | 49 Hz | Held flat |
The clause this came from
Ordinul ANRE nr. 3/2023 din 18.01.2023 (MO Nr. 53/19.I.2023) — Art. 6 alin. (1) lit. a) + Tabelul 1 'Durata minimă în care IS trebuie să fie capabilă să rămână conectată la rețea (să producă, respectiv să consume energie electrică la o putere activă mai mică sau egală cu puterea nominală) pentru frecvențe care se abat de la valoarea nominală': 47,5–48,5 Hz minimum 30 de minute; 48,5–49 Hz minimum 30 de minute; 49–51 Hz nelimitat; 51,0–51,5 Hz 30 de minute.
How long must the plant keep operating outside nominal voltage under Romania (Transelectrica/ANRE storage norm)?
The ride-through envelopes above answer how deep a disturbance the plant must survive. These bands answer the other question Romania (Transelectrica/ANRE storage norm) settles: how long it must keep operating at a voltage that is off nominal but steady. On this code the voltage envelope above also reaches into this range, so the two figures meet rather than divide cleanly.
A blue band ending in an arrow runs on, because the code states no end for it; a copper bar stops at the time the code prints, and only that right-hand end is data — every bar starts at the left edge of the axis.
Binds category C and D storage at 110 kV and above (Art. 21(4)(a)); sites below 110 kV are covered by Art. 15(d) instead. Art. 21(4) also lets the TSO set shorter times for a high voltage with a low frequency, or a low voltage with a high frequency, and lets wider ranges or longer durations be agreed case by case — so these bars are the norm's default rather than a fixed limit, movable in either direction.
Steady-state voltage operating bands — 110 kV and 220 kV
u.r. (unități relative) — per-unit of the 1 u.r. reference voltage at the connection/delimitation point; table columns « Domeniu de tensiune » / « Perioadă de funcționare »
Steady-state voltage operating bands — 400 kV
u.r. (unități relative) — per-unit of the 1 u.r. reference voltage at the connection/delimitation point; table columns « Domeniu de tensiune » / « Perioadă de funcționare »
Operating requirements beyond the envelopes.
The figures above are what Romania (Transelectrica/ANRE storage norm) demands during a disturbance and while it sits off nominal. The rows below are the same regime’s operating and fault-response requirements — reactive capability, frequency response, continuous operating range, ramp rate and RoCoF withstand — each researched from the document its own row cites, separately from the plotted corpus. Every row carries its clause and a verbatim quote, so you can check it the same way, including the continuous-operating-range row the staircases above are drawn from.
| Requirement | What the code states | Clause |
|---|---|---|
| PF ≤ 0,9 at POC in both absorption and delivery; three automatic Q-control modes (Cat C/D) Reactive capability | Category C and D storage installations must be able to provide a power factor of at most 0,9 at the point of connection/delimitation, both when absorbing (charging) and when delivering (discharging) active power, and must be able to supply reactive power automatically in voltage-control, reactive-power-control or power-factor-control mode. The connection study must demonstrate 0,9 inductive ÷ 0,9 capacitive across the whole active-power range in generation and in consumption, with zero reactive exchange when active power is zero. Basis: power factor at the POC (Q relative to actual P). Binds storage explicitly — the whole norm is storage-specific (IS = instalatie de stocare a energiei electrice). Art. 21(1) binds category C and D IS (categories follow ANRE's generating-plant classification applied to IS by installed power, Art. 5). PF capability is symmetric: required 'atât la absorbție, cât și la evacuare de putere activă' (both charge and discharge). Priority differs by class: for Cat C active power has priority in PF control; for Cat D reactive power has priority. The ORR, in cooperation with the TSO (OTS = Transelectrica) and the IS operator, specifies which of the three Q-control modes applies (Art. 21(2)). The second quote is the DTIS notification-documentation requirement (Anexa nr. 2 pct. 8) requiring the network study to prove the 0,9 inductive–0,9 capacitive requirement over the full charge/discharge active-power range with zero reactive exchange at P = 0, plus attaching the P-Q diagram at the POC and the U/Q/Pmax diagram where requested. | Art. 21 alin. (1) lit. a) și b) + Anexa nr. 2 la norma tehnică, pct. 8 (PDF p. 19; MO p. 31) |
The clauses this row citesArt. 21 alin. (1) lit. a) și b) — “ IS de categorie C și D trebuie să fie capabile: a) să asigure un factor de putere de cel mult 0,9, în punctul de racordare/delimitare, după caz. Pentru IS de categorie C, în reglajul factorului de putere este prioritară puterea activă, iar pentru IS de categorie D este prioritară puterea reactivă, atât la absorbție, cât și la evacuare de putere activă; b) să furnizeze automat putere reactivă în modul de reglaj al tensiunii, în modul de reglaj al puterii reactive sau în modul de reglaj al factorului de putere; ” Translation: “ Storage installations of category C and D must be capable of: a) providing a power factor of at most 0,9 at the point of connection/delimitation, as applicable. For category C storage installations, active power has priority in power-factor control, while for category D storage installations reactive power has priority, both when absorbing and when delivering active power; b) automatically supplying reactive power in voltage control mode, in reactive power control mode or in power factor control mode; ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) Anexa nr. 2 la norma tehnică, pct. 8 (PDF p. 19; MO p. 31) — “ 8. studiul de rețea pentru calculul necesarului de putere reactivă în punctul de racordare, pentru îndeplinirea cerințelor privind puterea reactivă în punctul de racordare (0,9 inductiv ÷ 0,9 capacitiv) pe toată plaja de putere activă în regim de generare (evacuare) și în regim de consum (absorbție), cu asigurarea schimbului de reactiv nul cu sistemul în situația în care puterea activă produsă/consumată este nulă. Se atașează diagrama P-Q a IS în punctul de racordare și diagrama U/Q/Pmax pentru categoriile de IS unde sunt solicitate; ” Translation: “ 8. the network study for the calculation of the reactive power requirement at the connection point, for the fulfilment of the requirements regarding reactive power at the connection point (0,9 inductive ÷ 0,9 capacitive) over the entire active power range in generation (export) mode and in consumption (absorption) mode, while ensuring zero exchange of reactive power with the system in the situation where the active power produced/consumed is zero. The P-Q diagram of the IS [instalație de stocare, storage installation] at the connection point and the U/Q/Pmax diagram are to be attached for the categories of IS where these are requested; ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) | ||
| Zero reactive exchange at P = 0; tolerance ≤ 0,5 MVAr (≥ 110 kV / station busbar) or ≤ 0,1 MVAr (MV lines) Reactive capability | Category B, C and D storage installations must compensate the reactive power of the HV line or cable between the HV terminals of the IS step-up transformer and the point of connection/delimitation. The compensation study is set for zero reactive-power exchange at zero active-power exchange at the POC, with a tolerance of at most 0,5 MVAr where the POC voltage is ≥ 110 kV or the POC is at station busbars, and at most 0,1 MVAr for IS connected on lines or at the end of a long MV line (the source's medium-voltage qualifier 'de MT' attaches to the long-line case). Basis: MVAr at the POC at P = 0. Binds storage explicitly (Cat B, C and D IS) at the point of connection/delimitation. If the IS cannot fully provide the additional reactive power, dedicated equipment supplied by the IS operator must provide it. The additional reactive power is fixed by a reactive-power compensation study at the POC. | Art. 20 |
The clause this row citesArt. 20 — “ IS de categorie B, C și D trebuie să fie capabile să compenseze puterea reactivă a liniei sau a cablului de înaltă tensiune între bornele de înaltă tensiune ale transformatorului ridicător de tensiune al IS și punctul de racordare/delimitare, după caz. Puterea reactivă suplimentară trebuie să fie asigurată de IS sau printr-un echipament dedicat pus la dispoziție de către gestionarul IS dacă IS nu poate asigura în totalitate puterea reactivă suplimentară. Această putere reactivă suplimentară este stabilită printr-un studiu de compensare a puterii reactive în punctul de racordare/delimitare, după caz, schimb de putere reactivă zero, la puterea activă nulă schimbată în punctul de racordare/delimitare, după caz, cu o toleranță: de maximum 0,5 MVAr dacă tensiunea în punct de racordare/delimitare, după caz, este ≥110 kV sau dacă punctul de racordare/delimitare, după caz, este situat la barele stațiilor electrice, respectiv maximum 0,1 MVAr pentru IS racordate în linii sau la capătul unei linii lungi de MT. ” Translation: “ Storage installations of category B, C and D must be capable of compensating the reactive power of the high-voltage line or cable between the high-voltage terminals of the IS step-up transformer and the point of connection/delimitation, as applicable. The additional reactive power must be provided by the IS or by dedicated equipment made available by the IS operator if the IS cannot fully provide the additional reactive power. This additional reactive power is established through a reactive-power compensation study at the point of connection/delimitation, as applicable, [with] zero reactive-power exchange at zero active power exchanged at the point of connection/delimitation, as applicable, with a tolerance: of at most 0,5 MVAr if the voltage at the point of connection/delimitation, as applicable, is ≥ 110 kV or if the point of connection/delimitation, as applicable, is located at the busbars of electrical stations, respectively at most 0,1 MVAr for IS connected on lines or at the end of a long MV line. ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) | ||
| Overfrequency response RFA-CR (LFSM-O analogue): threshold 50,2 Hz, droop 2–12 % (default 5 %), delay < 500 ms, ≤ 2 s for 50 % Pmax Frequency response | All IS with installed power ≥ 0,8 kW operating in production (discharge) mode must provide RFA-CR (limited active-power frequency response to overfrequency): activation threshold 50,2 Hz; set droop s2 between 2 % and 12 %, normally set at 5 %; initial delay less than 500 ms (longer must be technically justified to the ORR); response time for the power reduction ≤ 2 seconds for a power change of 50 % of Pmax. The IS must be able to reduce active power down to and including transition into consumption (charging) mode. Basis: Pmax of the IS. Binds storage explicitly; applies to every IS with Pi ≥ 0,8 kW in production mode (note the very low 0,8 kW threshold — this requirement is not category-gated). RFA-CR is the Romanian storage-norm analogue of LFSM-O ('reglaj de frecvență activ limitat la creșterea frecvenței', defined in Art. 4 lit. j) and abbreviated in Art. 4 lit. bb)). Droop is set at commissioning and can be changed by dispatcher order of the ORR. A distinctive storage feature: the response explicitly includes crossing into active-power consumption from the network. Per Art. 7 lit. c), when RFA-CR is active its setpoint (including transition to consumption) prevails over any active-power reference; the reservoir-not-depleted proviso is printed on the article's stable-operation sentence (the IS must operate stably provided the storage reservoir is not depleted), not on the prevalence sentence itself. | Art. 7 lit. a) |
The clause this row citesArt. 7 lit. a) — “ Art. 7. — IS cu Pi mai mare sau egală cu 0,8 kW, funcționând în regim de producere de energie electrică, trebuie să aibă capabilitatea de a asigura RFA-CR la creșterile de frecvență peste valoarea nominală de 50 Hz, astfel: a) la creșterile de frecvență, IS trebuie fie capabile să scadă puterea activă produsă, inclusiv să fie capabile să treacă în regim de consum de putere activă din rețea, corespunzător variației de frecvență, în conformitate cu figura 1 și cu următorii parametri: (i) pragul de frecvență de la care IS asigură răspunsul la creșterea de frecvență este 50,2 Hz; (ii) valoarea statismului setat (s2) se situează între 2% și 12%, este stabilită la punerea în funcțiune a IS și poate fi modificată de ORR prin dispoziții de dispecer. De regulă valoarea statismului se stabilește la valoarea de 5%; (iii) IS funcționând în regim de producere de energie electrică trebuie să fie capabile să scadă puterea activă corespunzător variației de frecvență cu o întârziere inițială mai mică de 500 ms (denumită întârziere și notată t1 în figura 7). În cazul în care această întârziere este mai mare de 500 ms, gestionarii IS justifică această întârziere, furnizând ORR motive de natură tehnică. Timpul de răspuns pentru scăderea de putere în cazul creșterii de frecvență trebuie să fie mai mic sau egal cu 2 secunde pentru o variație de putere de 50% din Pmax; ” Translation: “ Art. 7. — IS with Pi greater than or equal to 0,8 kW, operating in electricity production mode, must have the capability to provide RFA-CR at frequency rises above the nominal value of 50 Hz, as follows: a) at frequency rises, the IS must be capable [sic] of reducing the active power produced, including being capable of passing into active-power consumption mode from the network, corresponding to the frequency variation, in accordance with figure 1 and with the following parameters: (i) the frequency threshold from which the IS provides the response to the frequency rise is 50,2 Hz; (ii) the value of the set droop (s2) lies between 2% and 12%, is established at the commissioning of the IS and may be modified by the ORR through dispatcher orders. As a rule the droop value is set at the value of 5%; (iii) IS operating in electricity production mode must be capable of reducing active power corresponding to the frequency variation with an initial delay of less than 500 ms (called delay and denoted t1 in figure 7). If this delay is greater than 500 ms, the IS operators shall justify this delay, providing the ORR with technical reasons. The response time for the power reduction in the case of a frequency rise must be less than or equal to 2 seconds for a power variation of 50% of Pmax; ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) | ||
| Underfrequency response RFA-SC (LFSM-U analogue): threshold 49,8 Hz, droop 2–12 % (default 5 % = 8 % Pmax), ≤ 10 s for 50 % Pmax Frequency response | Category C and D IS in production mode must provide RFA-SC (limited active-power frequency response to underfrequency): mobilise active power — including switching from consumption (charging) to production mode, subject to reservoir availability — when frequency falls below the 49,8 Hz threshold, with droop set by the TSO within (2÷12) %, normally 5 % (which corresponds to an active-power mobilisation of 8 % Pmax); power increase up to maximum/admissible power with a response time ≤ 10 seconds for a power variation of at most 50 % of maximum power. Basis: Pmax of the IS. Binds storage explicitly; scope is category C and D IS in production mode (unlike RFA-CR, which binds from 0,8 kW). RFA-SC is the storage analogue of LFSM-U (defined Art. 4 lit. k), abbreviation Art. 4 lit. cc)). Droop is set by the TSO (OTS = Transelectrica) at commissioning or by dispatcher order. Delivery must account for the environmental-dependence diagram of active power and the Art. 8/9 admissible power-reduction limits at low frequency. Per Art. 16(2), activation must not be unduly delayed; a dead time t1 greater than 500 ms must be justified to the TSO. Per Art. 16(5), for Δf below -200 mHz the IS must increase active power according to droop s2 of figure 5. | Art. 16 alin. (1) lit. a) + Art. 16 alin. (3) (same PDF p. 8) |
The clauses this row citesArt. 16 alin. (1) lit. a) — “ Art. 16. — (1) IS de categoria C și D funcționând în regim de producere de energie electrică trebuie să asigure răspunsul limitat la abaterile de frecvență în cazul scăderii frecvenței (RFA-SC), după cum urmează: a) trebuie să poată mobiliza puterea activă, inclusiv prin trecerea din regim de consum (încărcare) în regim de producere de energie electrică, în funcție de disponibilitatea rezervorului, ca răspuns la scăderea frecvenței sub un prag de frecvență de 49,8 Hz și cu un statism stabilit de OTS la PIF sau prin dispoziții de dispecer în limitele (2÷12)%, de regulă la valoarea de 5%, ceea ce corespunde unei mobilizări de putere activă de 8% Pmax, în conformitate cu figura 5; ” Translation: “ Art. 16. — (1) Category C and D IS operating in electricity production mode must provide the limited response to frequency deviations in the case of falling frequency (RFA-SC), as follows: a) they must be able to mobilise active power, including by passing from consumption (charging) mode into electricity production mode, depending on the availability of the reservoir, as a response to the frequency falling below a frequency threshold of 49,8 Hz and with a droop established by the TSO at commissioning or through dispatcher orders within the limits (2÷12)%, as a rule at the value of 5%, which corresponds to an active-power mobilisation of 8% Pmax, in accordance with figure 5; ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) Art. 16 alin. (3) (same PDF p. 8) — “ La funcționarea în modul RFA-SC, IS funcționând în regim de producere de energie electrică trebuie să asigure o creștere de putere până la puterea maximă/admisibilă. Timpul de răspuns la creșterea de putere trebuie să fie mai mic sau egal cu 10 secunde la o variație de putere de maximum 50% din puterea maximă. ” Translation: “ When operating in RFA-SC mode [limited active-power frequency response at underfrequency, the LFSM-U analogue], the IS [instalație de stocare, storage installation] operating in electricity production mode must ensure a power increase up to the maximum/admissible power. The response time for the power increase must be less than or equal to 10 seconds for a power variation of at most 50% of the maximum power. ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) | ||
| Frequency-sensitive mode RFA (FSM analogue): adjustable deadband and droop (default s1 = 5 %), t1 = 500 ms, full activation ≤ 10 s, sustain ≥ 15 min Frequency response | Category C and D IS must additionally (cumulatively with Art. 16) provide RFA (active frequency response to frequency deviations in both directions): frequency deadband and droop modifiable at the TSO's disposal, droop s1 normally 5 % (corresponding to an active-power mobilisation of 8 % Pmax); for a step frequency change, full activation of the required active-power response with a delay (t1) of 500 ms and a maximum full-activation time (t2) of 10 seconds; and capability to sustain the frequency-response active power for a minimum of 15 minutes, as specified by the TSO. Basis: Pmax of the IS. Binds storage explicitly; scope is category C and D IS. RFA is the storage analogue of FSM ('reglaj de frecvență activ răspuns la abaterile de frecvență', Art. 4 lit. l), abbreviation Art. 4 lit. aa)). Art. 17 lit. a): on overfrequency the response may be provided by reducing produced power down to zero production; on underfrequency by reducing consumed power; actual delivery depends on operating conditions and stored-energy limits. Parameter ranges are set by the TSO within Table 6 (deadband in mHz, insensitivity zone, droop) and Table 7 (ΔP1/Pmax range, t1, t2) — both tables are reproduced in facsimile in the gazette PDF and their cell text does not survive text extraction, so the numeric values here are quoted from the Art. 17 prose, which restates t1 = 500 ms and t2 = 10 s. The ≥ 15 minute sustained-response duration (lit. e)) is a key energy-sizing constraint for BESS. | Art. 17 lit. b) și c) + Art. 17 lit. e) (same PDF p. 9) |
The clauses this row citesArt. 17 lit. b) și c) — “ b) să poată modifica banda moartă de frecvență și statismul, la dispoziția OTS. De regulă, valoarea statismului s1 este de 5%, ceea ce corespunde unei mobilizări de putere activă de 8% Pmax; c) în cazul variației treaptă a frecvenței, să fie capabilă să activeze integral puterea activă necesară ca răspuns la abaterea de frecvență, până la sau peste linia din figura 7, în conformitate cu parametrii prevăzuți în tabelul 7, în absența limitărilor de ordin tehnologic, și anume: cu o întârziere (t1) de 500 ms și un timp de activare de maximum 10 secunde (t2); ” Translation: “ b) [the IS must] be able to modify the frequency deadband and the droop, at the disposal of the TSO. As a rule, the value of droop s1 is 5%, which corresponds to an active-power mobilisation of 8% Pmax; c) in the case of a step variation of frequency, [the IS must] be capable of fully activating the active power required as a response to the frequency deviation, up to or above the line in figure 7, in accordance with the parameters set out in table 7, in the absence of technological limitations, namely: with a delay (t1) of 500 ms and an activation time of at most 10 seconds (t2); ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) Art. 17 lit. e) (same PDF p. 9) — “ e) trebuie să aibă capabilitatea de a furniza puterea activă corespunzător abaterii de frecvență pe o durată de minimum 15 minute, specificată de OTS; ” Translation: “ e) it must have the capability of supplying the active power corresponding to the frequency deviation for a duration of minimum 15 minutes, specified by the OTS [operatorul de transport și de sistem, transmission system operator]; ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) | ||
| Frequency bands 47,5–51,5 Hz with minimum durations; voltage bands 0,85–1,15 u.r. (110/220 kV) and 0,85–1,10 u.r. (400 kV) Continuous operating range | Frequency (all IS ≥ 0,8 kW, Art. 6(1)(a) + Table 1): 47,5–48,5 Hz minimum 30 minutes; 48,5–49 Hz minimum 30 minutes; 49–51 Hz unlimited; 51,0–51,5 Hz 30 minutes. Voltage (Cat C/D IS, Art. 21(4)(a) + Tables 8-9, per-unit of reference voltage 1 u.r.): at 110 kV and 220 kV — 0,85–0,90 u.r. 60 minutes, 0,90–1,118 u.r. unlimited, 1,118–1,15 u.r. 30 minutes; at 400 kV — 0,85–0,90 u.r. 60 minutes, 0,90–1,05 u.r. unlimited, 1,05–1,10 u.r. 30 minutes. Binds storage explicitly. Frequency bands bind every IS with Pi ≥ 0,8 kW, and Art. 6(1)(a) requires the IS to remain connected and operate (deliver or absorb energy) in these bands, i.e. these are operating bands, not mere connection-tenure bands. Voltage tables bind category C and D IS at POC voltages ≥ 110 kV (Art. 21(4) lit. a)); for POC voltages below 110 kV, Art. 15 lit. d) requires the IS to remain connected without reducing power (within stored-energy limits) as long as frequency stays within Table 1 and voltage within ±10% Un. Art. 21(4) lit. b): the TSO may set shorter times for simultaneous high-voltage/low-frequency or low-voltage/high-frequency; lit. c): wider ranges or longer durations may be agreed — where 20-minute operation is agreed in the 1,118–1,15 u.r. band, the maximum cannot exceed 60 minutes. The ride-through section on this page cites Tabelul 1 with a longer caption that includes '(să producă, respectiv să consume energie electrică la o putere activă mai mică sau egală cu puterea nominală)'; the Monitorul Oficial PDF as fetched prints the shorter caption quoted here, and the operate-while-connected element sits in Art. 6(1)(a) itself. | Art. 6 alin. (1) lit. a) + Tabelul 1 (PDF p. 4; MO p. 16) + Art. 21 alin. (4) lit. a) + Tabelul 8 și Tabelul 9 (PDF p. 13; MO p. 25) |
The clauses this row cites Art. 6 alin. (1) lit. a) + Tabelul 1 (PDF p. 4; MO p. 16) —
“
Tabelul 1. Durata minimă în care IS trebuie să fie capabilă să rămână conectată la rețea pentru frecvențe care se abat de la valoarea nominală Art. 21 alin. (4) lit. a) + Tabelul 8 și Tabelul 9 (PDF p. 13; MO p. 25) — “
Tabelul 8. Durata minimă de funcționare a unei IS racordate la tensiunea de 110 kV, respectiv 220 kV | ||
| Reconnection ramp 10–20 % Pmax/min after automatic reconnection; operational ramp rate settable by agreement (no fixed number) Ramp rate | After an incidental disconnection caused by a network event, automatic reconnection of an IS (Pi ≥ 0,8 kW) is normally permitted within the frequency range (47,5÷51) Hz and voltage range (0,9÷1,1)Un, within at most 300 seconds, and the admissible ramp for the active-power increase after connection must lie in the interval (10÷20) % of Pmax per minute in production mode. No numeric ramp limit is stated for normal operation: Cat B/C/D IS must have an active-power control system allowing the requested active-power ramp rate to be adjusted, as agreed between the IS operator, the TSO and the ORR. Basis: Pmax per minute. Binds storage explicitly. The numeric ramp band (10–20 % Pmax/min) applies only to the active-power increase after automatic reconnection, in production (discharge) mode; the conditions are set by the ORR in agreement with the TSO and communicated at ATR issuance (Art. 10(1),(3)). For normal operation the norm requires ramp-rate adjustability (Art. 14 lit. c), quote2) but fixes no number; ramp limiting also appears last in the control-priority hierarchy of Art. 19(3) ('d) limitarea rampelor de variație a puterii'), after protection, frequency control and power restrictions. | Art. 10 alin. (2) lit. b) și c) + Art. 14 lit. c) (PDF p. 7; MO p. 19) |
The clauses this row citesArt. 10 alin. (2) lit. b) și c) — “ b) cerința ca, de regulă, reconectarea automată să se realizeze în domeniul de frecvență (47,5÷51) Hz, de tensiune (0,9÷1,1)Un și într-un timp de maximum 300 de secunde; c) cerința ca rampa admisă pentru creșterea puterii active după conectare să fie cuprinsă în intervalul (10÷20)% din Pmax/min în regim de producere de putere activă. ” Translation: “ b) the requirement that, as a rule, automatic reconnection be carried out within the frequency range (47,5÷51) Hz, the voltage range (0,9÷1,1)Un and within a time of at most 300 seconds; c) the requirement that the admissible ramp for the increase of active power after connection be comprised in the interval (10÷20)% of Pmax/min in active-power production mode. ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) Art. 14 lit. c) (PDF p. 7; MO p. 19) — “ c) reglarea vitezei de variație a puterii active solicitate, agreate de gestionarul IS cu OTS și ORR, în funcție de performanțele IS și de tehnologia utilizată. ” Translation: “ c) the adjustment of the rate of variation of the requested active power, as agreed by the manager of the IS [instalație de stocare, storage installation] with the OTS [operatorul de transport și de sistem, transmission system operator] and the ORR [operatorul de rețea relevant, relevant network operator], depending on the performance of the IS and the technology used. ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) | ||
| RoCoF withstand: 2 Hz/s (500 ms window) / 1,5 Hz/s (1 000 ms) / 1,25 Hz/s (2 000 ms) RoCoF withstand | All IS with installed power ≥ 0,8 kW must remain connected and operate (deliver or absorb electricity) for rates of change of frequency of 2 Hz/s over a 500 ms time interval, or 1,5 Hz/s over a 1 000 ms time interval, or 1,25 Hz/s over a 2 000 ms time interval — the applicable value depending on the technology type, the system short-circuit power at the connection point (value stated by the ORR in the ATR) and the inertia available in the synchronous area. Binds storage explicitly (all IS with Pi ≥ 0,8 kW, both charge and discharge — 'să evacueze, respectiv să absoarbă'). The measuring windows are stated (500/1 000/2 000 ms). Per Art. 6(2) the applicable values are communicated to the IS operator when the connection approval (ATR) is issued; per Art. 6(3) the protection settings at the connection point coordinated by the ORR must permit IS operation for these frequency-variation profiles. The same withstand profile is re-listed as a conformity-verification item in Anexa nr. 2 pct. 4 lit. c) (PDF p. 18). | Art. 6 alin. (1) lit. b) |
The clause this row citesArt. 6 alin. (1) lit. b) — “ b) să rămână conectată la rețea și să funcționeze (să evacueze, respectiv să absoarbă energie electrică) în cazul unor viteze de variație a frecvenței de 2 Hz/s pentru un interval de timp de 500 ms sau de 1,5 Hz/s pentru un interval de timp de 1.000 ms sau de 1,25 Hz/s pentru un interval de timp de 2.000 ms, în funcție de tipul de tehnologie, de puterea de scurtcircuit a sistemului în punctul de racordare (valoare precizată de ORR prin ATR) și de inerția disponibilă la nivelul zonei sincrone. ” Translation: “ b) [the IS must] remain connected to the network and operate (deliver, respectively absorb electricity) in the case of rates of frequency variation of 2 Hz/s for a time interval of 500 ms or of 1,5 Hz/s for a time interval of 1 000 ms or of 1,25 Hz/s for a time interval of 2 000 ms, depending on the type of technology, on the short-circuit power of the system at the connection point (value specified by the ORR through the ATR) and on the inertia available at the level of the synchronous area. ” (Ordinul ANRE nr. 3/2023 pentru aprobarea Normei tehnice privind cerintele tehnice de racordare la retelele electrice de interes public pentru instalatiile de stocare a energiei electrice si procedura de notificare pentru racordarea instalatiilor de stocare a energiei electrice (Monitorul Oficial al Romaniei, Partea I, Nr. 53/19.I.2023), accessed 2026-08-08) | ||
Who does Romania (Transelectrica/ANRE storage norm) bind, and since when?
Category D electricity storage installations (RfG type D). No date of effect is published here — grid codes are reissued, so check the current issue before relying on it.
These figures are a reading aid, not legal advice. Grid codes are reissued: verify against the current edition before you design to them.
Curve data last checked against the code on — 66 standards, 130 envelopes, published by bess.engineer under CC BY 4.0.
Questions this page answers about Romania (Transelectrica/ANRE storage norm)
- Does Romania (Transelectrica/ANRE storage norm) require ride-through, or only that the plant does not trip?
- Ride-through. Every envelope on this page is a performance duty the plant must meet, not a protection-setting no-trip boundary — they are different obligations. That is what these curves are; they are not everything Romania (Transelectrica/ANRE storage norm) contains. The requirement sentence under each chart says which side of the curve is the compliant one.
- Are the numbers on this page taken from Romania (Transelectrica/ANRE storage norm) itself?
- Every breakpoint is read from the code, and where a point was taken off a published figure rather than stated in the clause, the section under that chart says so — on this page that includes an envelope that stops where its published chart stops. The clause each curve came from is quoted under it.
- Which events are charted for Romania (Transelectrica/ANRE storage norm)?
- Romania (Transelectrica/ANRE storage norm) is charted here with 2 envelopes — low-voltage ride-through, frequency ride-through (LVRT, FRT). No high-voltage envelope is charted here — check Romania (Transelectrica/ANRE storage norm) itself before concluding it sets none. Its steady-state voltage-band figures add 2 more, drawn from the code's continuous-operating-range table rather than from a ride-through curve.
Ride-through, in context.
An envelope is a compliance boundary; understanding why it exists is a different question. The ride-through and grid-forming entries cover the engineering, and the Engineering Foundations course builds it from the physics up.
Elsewhere in Europe: Poland (PSE Wymogi 2025), Spain (P.O. 12.3), Sweden (EIFS 2018:2), Switzerland (Swissgrid CESS minimum), Switzerland (Swissgrid TC-CH 2019), Turkey (TEİAŞ Şebeke Yönetmeliği Ek-18), and 13 more