Update of the system to the CEI 0-16 law for Installations Connected to the MT Network
The update of an installation to the CEI standard
0-16 low has several advantages, including:
- increase reliability and safety of the system
- stop payment of the “Specific fee – CTS” or “Larger Specific Fee Card – CTSM”
- receive automatic compensation in case of prolonged interruption of electricity supply (2 long breaks for towns with more than 50,000 inhabitants).
The automatic compensation amounts to 1.75 [€ / kW] * P [kW] for customers with average power interrupted less than or equal to 500 kW; 1.4 [€ / kW] * P [kW] for average power interrupted more than 500 kW (the average interrupted power is equal to 70% of the available power).
If the system in MT is not update to the current CEI regulation 0-16 the customer does not receive any indemnity, even if the conditions exist , and is obliged to pay the Specific Fee – CTS – or increased – CTSM.
Technical Requirements for a system Connected to the MT Network
The technical requirements that a system must have to take advantage of the condition specified above are decidec by the. A to Del. ARG / elt 198/11, and involve the presence of:
- General device (DG) consisting of a disconnecting switch and a switchgear or a switch of the withdrawable type;
- General protections (PG), able to divide the polyphase faults and single-phase earth faults, downstream of the DG.
- Calibration of the General Protections carried out according to the indications of the distributing company, and maintenance of the same.
- Tests on the DG + PG complex carried out according to the Authority’s indications.
In according with derogation from the above technical requirements, MV customers with available sampling power of less than or equal to 400 kW may limit themselves to the following requirements:
- be equipped with a switch-disconnector (IMS) with fuses and a single MV / LV transformer with power not exceeding 400 kVA, or be equipped with a low oil volume switch (IVOR) with a protection device for at least current short circuit and a single MV / LV transformer with power not exceeding 400 kVA, or be equipped with an equivalent circuit breaker with a protection device at least for short-circuit current and a single MV / LV transformer with power not exceeding 400 kVA ;
- the MT connection between the IMS and the MV / LV transformer or between the IVOR and the MV / LV transformer or between the equivalent circuit breaker and the MV / LV transformer must be made of a cable with a total length not exceeding 20 m ;
- perform maintenance in accordance with CEI 0-15 low;
- be equipped with a Maneuvering Switch Combined isolator with fuses equipped with earth fault relay (IMS-FGT-R);
- be equipped with a single MV / LV transformer with power not exceeding 400 kVA;
- the MT connection between the IMS-FGT-R and the MV / LV transformer must be made of a cable with a total length not exceeding 20 m.
What is the CTS?
The specific price or CTS is a fee charged in the monthly invoice by the distributor company to its MT users, both in withdrawal and in intake, having the following characteristics:
- medium voltage customers who did not deliver the adequacy declaration of the system to the electricity distributor and the system connection request was made before November 16, 2006;
- the declaration of adequacy was cancelled by the distributor after controlling that showed the non-compliance of the system with the technical requirements of Resolution ARG / elt 198/11 and of Resolution ARG / elt 33/08.
Value of the CTS
The CTS correspond, on an annual basis, to:
- 500.00 € for MV users with PD equal to or less than 400 kW;
- (500 + 750 * [(PD-400) / 400]) € for MV users with PD greater than 400 kW and less than or equal to 3,000 kW;
- € 3,280.36 for MT users with PD above 3,000 kW,
where PD is the maximum value between the available power and the available input power evaluated at 1 January of the year to which the calculation of the CTS refers.
The payment of the CTS is stopped when the declaration of adequacy is sent to the distributing company.
What is CTSm?
The attach. B to Del. ARG / elt 33/08 introduces the Specific Larger fee or CTSm.
The CTSm fee is applied to replace the CTS to customers in MT in the following cases:
- for customers with an available power of less than or equal to 400 kW, power increases of at least 50 kW have been requested, or systematic power withdrawals beyond that available, starting from 1 September 2008;
- for customers with an available power of more than 400 kW, power increases of at least 100 kW have been requested, or systematic power withdrawals have been applied beyond that available, starting from 1 September 2008
- since 1 September 2008, has been requested an increase in power, resulting in the exceeding of 400 kW;
- have been made requests for takeover of a pre-existing user with a duration of less than one year and simultaneous increases in power according to the aforementioned thresholds .
Through a visual inspection of the transformer cabin and a check of the mechanical conditions and of the state of maintenance of the trnsformer, it will be possible to establish the need for replacement of the components, which must take place in the following cases:
- the general device (DG) does not comply with the minimum requirements set by the att. C to the Del. ARG / elt 33/08;
- the intervention time of the SPG + DG system, verified by means of an appropriate instrument, does not comply with the values indicated in Annex B of CEI 0-16.
Following the replacement of the General Protection System (SPG) and the TA and TO, the intervention time will be tested (which must remain below 200 ms), and the following documentation will be released:
- test report of the verification of the intervention times;
- declaration of adequacy
- measurement of the earth resistance values, which must comply with the requirements of the CEI 99-3 standard.