Network Codes are a set of rules developed by ENTSO-E, with the support of the Agency for the Cooperation of Energy Regulators (ACER), aimed at facilitating the harmonization, integration, and efficiency of the European electricity market. A distinctive variant of Network Codes are the Connection Network Codes (CNC), which include NC RfG, NC DCC, and NC HVDC (Connection of Power Generating Modules, Connection of Demand, and Connection of High Voltage Direct Current Systems).

ENTSO-E stands for the European Network of Transmission System Operators for Electricity. It is an organization comprising electricity transmission system operators (TSOs) from European countries, aimed at cooperation in managing and developing the electricity transmission networks across Europe.

A Power Generating Module (PGM) is defined in EU Regulation 2016/631 (NC RfG) as an aggregate category encompassing Synchronous Power Generating Modules (SPGM) and Power Park Modules (PPM). According to the definitions of SPGM and PPM, and the so-called Network Codes Implementation Guidance, a PGM includes a set of devices, networks, and installations capable of generating electricity and feeding it into the system operator’s network, having one connection point to that network. PGMs are categorized based on two main criteria: the maximum power (Pmax) and the network voltage level, as well as two properties: the location of the connection point (offshore or onshore) and the predominant mode of operation (synchronous or asynchronous). This categorization allows for the specification of technical requirements and compliance verification methods for PGMs. The primary rationale for such categorization is to match the requirements to the actual impact of Power Generating Modules on the stability of the electrical grid. It’s worth noting that the origin of the primary energy source is not a classification criterion; energy can be generated from various sources and fed into the network at a single connection point within one PGM.

According to the definition (NC RfG DC Recommendation: Annex 1 Amended RfG Regulation), a Power Generating Unit (PGU) means an aggregation of components converting a primary source of energy into electricity at the terminals of a unit generating electricity, which is either synchronously connected to the network, nonsynchronously connected to the network, or connected through power electronics.

As defined in the CNC NC RfG (EU Regulation 2016/631), a Power Park Module (PPM) means a unit or a set of units generating electricity (PGU), which is connected to the network either nonsynchronously or through power electronics, and which also has one connection point to the transmission system, distribution system, including a closed distribution system, or an HVDC system.