BS/EN 50549-1-2019 pdf download.Requirements for generating plants to be connected in parallel with distribution networks Part 1: Connection to a LV distribution network – Generating plants up to and including Type B.
This clause defines the requirements on generating plants to be operated in parallel with the distribution network. Where settings or a range of configurability is provided and respecting the legal framework the configurations and settings may be provided by the DSO. Where no settings are provided by the DSO, the specified default settings shall be used; if no default settings are provided. the producer shall propose settings and inform the DSO.
The requirements of Clause 4 apply during normal operation of the generating units and do not apply in case of maintenance or units out of operation. The provisions apply to EESS in generation mode. In charging mode EESS should have the same characteristics, unless stated otherwise in the clauses of this European Standard.
The applicabthty is independent of the duration the generating unit operates in parallel with the distribution network. It is the responsibility of the DSO to relax, if deemed appropriate, the requirements for an individual generating unit or plant whose operation in parallel only lasts for a short time (temporary operation in paralle’). The relaxed requirements shall be agreed between the DSO and the producer, along with the maximum allowable duration of the temporary operation in parallel. For the short-term parallel operation an appropriate device shall automatically disconnect the generating unit or plant as soon as the maximum allowable duration has elapsed.
If different requirements on the generating plant interfere with each other, the following hierarchy in
descending order shall be applied:
1. Generating unit protection, including regarding the prime mover;
2. interface protection (see 4.9) and protection against faults within the generating plant:
3. voltage support during faults and voltage steps (see 4.7.4):
4. the lower value of: remote contro’ command on active power limitation for distribution grid security (see 4.11) and local response to overfrequency (see 4.6.1):
5. local response to underfrequency if applicable (see 4.6.2):
6. reactive power (see 4.7.2) and active power (P(U) see 4.7.2) controls;
7. other control commands on active power set point for e.g. market, economic reasons, self- consumption optimization.
The system shall be so designed that under foreseeable conditions no self-protection trips prior to the fulfilment of the requirements of this European Standard and all settings provided by the DSO or responsible party.
For cogeneration plants embedded in industrial sites, active power requirements shall be agreed between the responsible party and the producer. In such a case the priority list is adapted accordingly.
Besides the requirements of Clause 4, additional requirements apply for connecting a generating plant to the distribution network, e.g. assessment of the point of connection. However, this is excluded from the scope of this European Standard but some guidance is provided in the informative Annex A.
4.2 Connection scheme
The connection scheme of the generating plant shall be in compliance with the requirements of the DSO. Different requirements may be subject to agreement between the producer and the DSO depending on the power system needs.
Inter alia, the generating plant shall ensure the following:
• synchronization, operation and disconnection under normal network operating conditions, i.e. in the absence of faults or malfunctions;
• faults and malfunctions within the generating plant shall not impair the normal functioning of the distribution network;
• coordinated operation of the interface switch with the generating unit switch, the main switch and switches in the distribution network, for faults or malfunctions within the generating plant or the DSO network during operation In parallel with the distribution network; and
• disconnection of the generating plant from the distribution network by tripping the interface switch according to 4.9.
In order to satisfy the above functions, coordinated but independent switches and protection equipment may be applied in the generating plant, as shown in the example in Figure 2.
4.3 ChoIce of swltchgear
4.3.1 General
Switches shall be chosen based on the characteristics of the power system in which they are intended to be installed. For this purpose, the short circuit current at the installation point shall be assessed, taking into account, inter aiia. the short circuit current contribution of the generating plant.
4.3.2 Interface switch.BS/EN 50549-1-2019 pdf download.