Producers

Power connection >250 kW

Production units for self-consumption with a connected power >250 kW.

Installation of interconnection/homopolar protection


For Self-Consumption installations with a connection power exceeding 250 kW, the installation of interconnection/homopolar protection for grid connection purposes is not exempt.

According to the 'Technical Guide for Independent Power Generation Installations' and other applicable laws and regulations, the production installation must be equipped with protections, at the interconnection level, that ensure fast, effective and automatic separation from the electricity distribution grids, as well as provide the homopolar maximum voltage protection function.

Design elements required for technical analysis

Chapter 1. General documents:

General data regarding the self-consumption installation - Document containing the following information:

  • Customer Identification (Entity and NIF);
  • Consumption SPC;
  • Production PSC;
  • Production Unit Register Number assigned by the Directorate General for Energy and Geology (DGEG) Self-Consumption Portal;
  • Production Unit Registration No. assigned by the Self-Consumption Portal of the Directorate General for Energy and Geology (DGEG);
  • Installed power of the production unit in kVA;
  • Connection power of the production unit in kVA.
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Chapter 2. Protection system

  • Project description for the insertion of the Production Unit in the consumer installation;
  • Plan identifying the planned location of the interconnection protection system and the energy measurement, metering and telemetering system;
  • Identification plan with the constitution of the generating groups and their main characteristics;
  • Unifilar diagram of the insertion in the Public Service Electrical Network (RESP), with identification of the connection point and IT/TT, including the transformation ratio of both, as described in the operation protocol;
  • Schemes for electrification of the interconnection panel (according to the "good art rules"), including:
    • The interconnection protection relay should be unique and contain all the protection functions listed below. Likewise the measuring equipment (current transformers and voltage transformers) must be exclusive (sharing equipment with the DSO is not accepted) and suitable for the implementation of protection functions and must be installed at the grid connection voltage level because only in this way will the correct operation of all the protection functions be guaranteed.
    • Protection relay connections (including protection functions - ANSI codes, if applicable):
      • Maximum residual voltage / homopolar voltage [ANSI 59N];
      • Minimum three-phase voltage [ANSI 27];
      • Maximum three-phase voltage [ANSI 59];
      • Maximum frequency [ANSI 81O];
      • Minimum frequency [ANSI 81U];
      • Maximum 3-phase current [ANSI 50/51];
      • Maximum intensity of inverse sequence [ANSI 46];
      • Directional power [ANSI 32].

Technical characteristics of the equipment:

  • Protection relays (including the one provided for power limitation and maximum homopolar voltage, if applicable), equipment according to IEC 60255 standard;
  • Current and voltage transformers and their test reports;
  • Trip coils;
  • Interconnection circuit breaker, must comply with IEC 60947-1 and 60947-2 (for LV circuit breakers) and IEC 62271 (for MV and HV circuit breakers). The maximum isolation time (interval between the opening order and the opening of the contacts) must be 0.15s.

 

Chapter 3. Measurement and metering system

Schemes for electrification of the metering board (according to "good rules of art"):

  • Own counting of the generation (totalizer);
  • Interconnection metering with the grid;
  • Unifilar diagram of the installation that integrates the UPAC;
  • Complete single-line diagram containing all the other generation sources (cogeneration, mini, micro or UPP - only when there are other generation sources) electrically interconnected at the same point of the grid and any resource feeds;
  • Identification of the ownership of the metering equipment used for billing, associated with the consumption contract where the UPAC is to be installed
  • Identification of the busbar voltage level and TT and TI relationship.
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Technical characteristics of the totalizer meter:

  • Brand and model and respective technical data sheet of the meter;
  • Brand and model of modem and respective technical data sheet;
  • Meter test reports (in case tests have been carried out);
  • Meter serial number;
  • GSM Card number that must have the following characteristics:
    • Send data over voice (CS Data, or, CSD communication, i.e. "Circuit Switch Data" which is the communication of data over voice);
    • Allow only the reception of calls;
    • Do not allow outgoing calls (cannot make calls);
    • Should not have an active PIN, that is, a SIM card without PIN;
    • Should be a M2M (Machine to Machine) type card;
    • Should allow OTA (Over The Air technology) and STK (SIM ToolKit) commands;
    • It must have a capacity between 25MB and 250MB.

 

Please send the documents to produtores@e-redes.pt, indicating the DGEG registration number and the Delivery Point Code (CPE).

The technical analysis will be done as a whole, so it will be necessary to send all the documentation in pdf format.

 

Protection Tests

After the analysis of the documentation sent, the on-site monitoring of the interconnection protection tests of the production installation and respective regulation will be scheduled:

  • Performing tests on the Voltage Transformer (TT) and Intensity Transformer (TI) primaries and respective connections
  • Functional tests of the interconnection protection, settings and functions.

On-site monitoring

These tests must be carried out at a single time, but if it is not possible to reconcile them, the producer may, alternatively, present a document declaring the compliance of the primary tests, with only face-to-face monitoring by E-REDES of the functional tests.

 

E-REDES cannot be held responsible for any occurrences

E-REDES will not be held responsible for any occurrences and/or irregularities that may take place at the Manufacturing Plant, whether they originate from the plant or the grid, and that impact the safety of people, facilities (including the Manufacturing Plant itself) and/or property. It is the responsibility of the owner of the manufacturing plant to prove that the inverters and protections meet all the required technical conditions.

 

Consigning the customer's installation

If you wish to consign the customer's consumption installation to suit the self-consumption installation, you must make the request at least 7 working days in advance to the email address interrupcoes.programadas@e-redes.pt with the following information:

  • Delivery point code (CPE);
  • Brief description of the work to be carried out;
  • Date and time intended for the cut;
  • Date and time required for reconnection;
  • Name and cell phone contact of the technician responsible for the work;
  • If there are modifications to the private service electrical installation (under article 14 of Decree-Law 96/2017 of August 10, 2017), you must submit a provisional authorization issued by the DGEG.