(SA-E-20220110-001)
1
Application of Shunt Trip DC Switch on
String Inverter
As the installation of PV systems increases, the demand for effective electrical protection of PV systems are
becoming strong. Appropriate over-current protection for the PV modules are took into consideration based on
the IEC standard.
In DC side protection requirement of Photovoltaic (PV) arrays - IEC 62548, the main purpose is to protect
photovoltaic modules from damage caused by reverse current. However, there are no effective protection
measures and definitions in the current standards to protect the inverter from being damaged by the abnormal DC
input current.
In order to improve this part, some manufacturer choose the string-level fuse as the protection mechanism.
By implementing shunt trip DC switch, it can be used to protect the inverter from being damaged by DC short
circuit with MPPT more than two strings.
Lack of Protection Standard for DC Side of Inverter
Shunt Trip DC Switch Application on String Inverter
(SA-E-20220110-001)
2
Application of Shunt Trip DC Switch on
String Inverter
Working mechanism of shunt trip DC switch
The shunt release is an opening coil plus a release. By apply certain voltage to the shunt trip coil, the DC switch
will trip and open. The shunt release is often used in the control of long-distance automatic power-off based on
control logic combinations. As the DC switch is integrated on the GoodWe inverter, the inverter DSP can issue
commands to trip the DC switch and isolate the DC strings from the main input circuit of the inverter.
(SA-E-20220110-001)
3
Application of Shunt Trip DC Switch on
String Inverter
Remote shutdown functions based on shut trip DC switch
The software developed for the shunt trip switch in GW250KN-HT will:
1. Accumulate the trip times when the trip current is greater than 20A. Until the accumulated times exceed 10
times, a trip switch fault warning will be issued without affecting the normal grid connection of the inverter.
2. Record the trip time and be monitored by SolarGo App, and be reset to zero when being replaced.
Based on the above software logics, there are two major functions to protect the inverter:
Operation guide of shunt DC switch
1. The inverter happened with PV Reverse Polarity or PV Short Circuit, the DSP of inverter will trip the DC switch,
and trigger the following alarms accordingly, which will be showed in the LCD, SEMS and SolarGo:
1) PV Reverse Fault:
2) PV Short Failure
2. The O&M team heads to the project site to check the inverter with the fault alarm, clear the alarm and reset
the DC trip switch.
3. Reset the trip time on SolarGo when replacing the DC trip switch.
(SA-E-20220110-001)
4
Application of Shunt Trip DC Switch on
String Inverter
W
Welcome visiting GoodWe Solar Community (community.goodwe.com)
to check all technical articles, guidance videos, webinars and activities released by GoodWe and GoodWe Solar
Academy.
Notice
The information in this document is subject to change without notice, all information in this document do not constitute any kind
of warranty.Please check with GoodWe Solar Academy'[email protected]om' for the latest version.
1
/
4
100%
