This standard specifies the grid connection mode, power quality, safety and protection and installation requirements for PV system.
This standard is applicable to PV system connected with the grid in low-voltage mode through the static converter (inverter).
The relevant portion of PV system connected under medium-voltage or high-voltage also may refer to this standard.
2 Normative References
The following normative documents contain provision which, through reference in this text, constitute provisions of this national standard. For dated references, subsequent amendments (excluding correction to) to, or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 2297-1989 "Terminology for Solar Photovoltaic Energy System"
GB/T 12325-2003 "Power Quality-Admissible Deviation of Supply Voltage"
GB 2894-1996 "Safety Signs" (neq ISO 3864:1984)
GB/T 14549-1993 "Quality of Electric Energy Supply-Harmonics in Public Supply Network"
GB/T 15543-1995 "Quality of Electric Energy Supply-Admissible Three-phase Voltage Unbalance Factor"
GB/T 15945-1995 "Quality of Electric Energy Supply-Permissible Deviation of Frequency for Power System"
GB 16179-1996 "Guidelines for the Use of Safety Signs"
GB/T 18479-2001 "Terrestrial Photovoltaic (PV) Power Generating Systems--General and Guide"(idt IEC 61277:1995)
SJ/T 11127-1997 "Overvoltage Protection for Photovoltaic(PV) Power Generating Systems-Guide"
3 Definition
For the purpose of this standard, the following terms and definitions apply.
3.1
PV system
It is a system including all inverters (unit set or multi-sets) and relevant BOS (components of Balance of System) as well as a solar-cell-array (with one shared connection point) included.
3.2
Grid
The combination of all kinds of devices and equipments for power transmission and distribution, substations and power lines or cables, which connects the power plants and customers distributed in a broad region as a whole unit and delivers the centralized-generated power to numerous scattered power customers.
In this standard, it specially refers to the power transmission network for the secondary output of power transformer in power supply area to the customer side.
3.3
Grid protection device
It is the device that monitors the technical conditions of power connection of PV system and disconnects the PV system and the grid safely when the index is out of limit.
3.4
Grid-interface
It refers to the mutual linkage between PV system and the grid distribution system.
It generally refers to the connection points and disconnection points between the generating equipments and the grid.
3.5
Islanding
It refers to the condition that PV system still keeps continuous power for a certain part of lines in the voltage-loss grid when there is no voltage in the grid.
3.6
Inverter
Static power inverter (see Note 1).
It is the device that converts the direct current into the alternating current. It is the equipment that converts the direct current of PV system into the alternating current. It is an electrical equipment used for converting the electrical power into a kind of or multi-forms of electric power that is suitable for the grid.
Note 1: Any static power inverter that used for interfaces between the power supply and the grid with control, protection and filtration functions. Sometimes, it is called a power regulation subsystem, power conversion system, static converter or power regulation unit.
3.7
Emergency power supply system
It is a power supply system that is able to supply continuously for specific load when the grid is power off for reasons, generally including the inverter, protection switch, control circuit, energy storage device (such as a storage battery) and the charging set with a charging control circuit.
4 Connection Mode
The grid connection modes shall be divided into countercurrent and non-countercurrent modes according to whether PV system permits the transformer, by passing the power supply area, to transmit the power to high voltage grid.
GB/T 19939-2005 The following standards are cited：
