Technical differences between IEC 61643-31 vs IEC 61643-41

Differences in application and scope

Key technical differences

• IEC 61643-31 specifies requirements and test methods for SPDs installed on the DC side of photovoltaic power plants. It is intended only for SPDs permanently connected to the DC side of PV generators and inverters, and includes test items and performance criteria tailored to the specific operating conditions of PV systems (e.g. PV current, short-circuit current, DC arc, etc.).

• IEC 61643-41 specifies requirements and test methods for SPDs applicable to general low-voltage DC systems (e.g. industrial DC distribution, telecommunications, railways, etc.). It covers safety and performance requirements and test methods for various DC power environments, not limited to PV systems. It is a standard for more general DC environments, not PV-specific tests.

Differences in Test and Performance Requirements

• IEC 61643-31 : Reflecting the characteristics of PV systems, it includes additional tests for immunity to PV short-circuit current (ISCPV), DC arc, voltage fluctuations of PV modules, and safety requirements specific to PV systems. Test methods that reflect special situations such as overvoltage, overcurrent, and short circuits in the PV environment are applied.

• IEC 61643-41 : Provides test criteria for a more general DC environment, such as surge, temporary overvoltage (TOV), protective conductor current, operational endurance, and overload withstand in various DC power sources (e.g. batteries, DC distribution, etc.), applicable to the entire DC system. Does not include PV-specific tests.

Standard structure and application method

• IEC 61643-31 is specific to DC SPDs for PV installations and emphasizes special testing and safety requirements for the PV environment.

• IEC 61643-41 covers the entire DC system and provides generalized test and safety criteria that can be applied to various DC application environments, not just PV. It is applied in conjunction with IEC 61643-01 (Common Requirements).

summation

IEC 61643-31 is a standard specific to DC side SPDs of photovoltaic (PV) installations, and covers tests and requirements that reflect the special characteristics of the PV environment. On the other hand, IEC 61643-41 is not limited to PV, but targets SPDs for all low-voltage DC systems, and provides more general DC environment test and safety criteria. The biggest technical difference is that the scope of application and test requirements are divided into PV-specific (61643-31) and general DC system (61643-41), respectively.