Standards Development

Scope

As a part of lEC 62786, this Technical Specification provides general test requirements for distributed energy resources (DERs) connected to an electric power network (in the following: the "network"). It applies to the operation and connection of DER to networks. This document provides the testing conditions and testing procedures to verify the requirements specified in IEC TS 62786- 1 at plant level. The tests include general requirements, connection scheme, choice of switchgear, normal operating range, active power response to frequency deviation, reactive power response to voltage variations and voltage changes, EMC and power quality, interface protection, connection and start to generate electric power, active power management, monitoring, control, communication, etc. DER include distributed generation and electrical energy storage in the form of synchrono us generators, asynchronous generators, power converters, etc., connected to the medium voltage(MV) or low voltage (LV) network.

Purpose

The rapid development of DERs is facing various end -use environments, which brings many challenges to the safe and reliable operation of the grid connected with DERs. With the release of IEC TS 62786-1:

Distributed energy resources connection with the grid - Part 1: General requirements, it is urgent to develop corresponding testing standards to ensure that DERs connection with the grid meets the requirements such as control, interface, and communication, etc, which are specified in the IEC TS 62786-1. To ensure the safe and reliable operation of the grid and avoid the issues such as operation voltage exceeding limits, power supply reliability decreasing, and power quality deterioration, etc, the strict testing is required to ensure that connection of DERs with the grid does not pose a threat or interference to the grid operation. It is necessary to identify and minimise the DERs potential problems and improve its overall reliability and safety.

 Currently, there is no corresponding IEC standards that are able to provide the tests procedures to verify the requirements specified in IEC TS 62786-1. Compared with the proposed new standard, there will be not overlaps with existing lEC standards on control, interface, and communication, etc., as the existing standards cannot meet all testing needs of DERs connection with the grid. Here are some examples:

IEC TS 63102 Grid code compliance assessment methods for grid connection of wind and PV power plants. This standard recommends technical methods of grid code compliance assessment for grid connection of wind and PV power plants. However, the new proposal i s mainly concerned with testing methods of DERs, not the compliance assessment. Therefore, there is no overlap between new proposal and IEC TS 63102.

IEC TS 63605 ED1 Grid compliance test for PV power plants. This document is applicable to PV power plants connected to the POC at medium voltage, high voltage or extra high voltage level. However, the test objects for the new proposal are DERs connected to the MV or LV network specified in IEC TS 62786-1, which are not covered in this standard. Where for the compliance testing for PV power plant connected to MV network, care will be taken to ensure consistency and coordination with IEC TS 63605.

IEC TS 62910 Utility-interconnected photovoltaic inverters - Test procedure for under voltage ride- through measurements. This standard provides a test procedure for evaluating the performance of Under Voltage Ride-Through (UVRT) functions in inverters used in utility-interconnected Photovoltaic (PV) systems. The test objects and methods for the new proposal are not covered in this standard.

IEC TS 63217 Utility-interconnected photovoltaic inverters - Test procedure for over voltage ride- through measurements. This standard provides a test procedure for evaluating the performance of Over Voltage Ride-Through (OVRT) functions in inverters used in utility -interconnected photovoltaic (PV) systems. The test objects and methods for the new proposal are not covered in this standard.

IEC 62116 Utility-interconnected photovoltaic inverters - Test procedure of islanding prevention measures. This standard provides a test procedure to evaluate the performance of islanding prevention measures used with utility-interconnected PV systems. The test objects and methods for the new proposal are not covered in this standard.

IEC 61215 Terrestrial photovoltaic (PV) modules- Design qualification and type approval Part 1: Test requirements. This standard fail to define the test of PV connection to gird.

IEC 62933-2-1 Electrical energy storage (EES) systems - Part 2: Unit parameters and testing methods – General specification. This standards fail to define the tests of EES systems connection to the grid.

IEC 62933-2-2 Electrical energy storage (EES) systems - Part 2-2: Unit parameters and testing methods – Application and performance testing. These standards fail to define the tests of EES systems connection to the grid.