GYDCG-MBC Multi-Branch DC Insulation Monitor for Systems up to 1500VDC

Description

The GYDCG-MBC multi-branch DC insulation monitor checks the insulation of a DC system up to 1500VDC and of up to 30 individual branches at the same time. It consists of a main control module (GYDCG-MBC V1.0) and leakage current sensors (GYLCS), so a fault can be traced to the branch that causes it instead of only being reported for the whole system.

Product description

GYDCG-MBC Multi-Branch DC Insulation Monitoring System

The GYDCG-MBC Multi-Branch DC Insulation Monitoring System consists of a main control module (GYDCG-MBC V1.0) and multiple leakage current sensors (GYLCS).

The main control module is connected to the DC positive pole, negative pole, and ground. The positive and negative cables of each branch are connected in parallel through the leakage current sensors. The reference current direction marked on the sensor housing should match the cable current direction. The four control terminals of each leakage current sensor (G, M, -, +) are connected to the corresponding terminals (G, M, -, +) of the main control module channels B1~B30 to complete the system installation.

The B1~B30 ports of the main control module represent 1st to 30th branch channels. The leakage current sensors must be connected sequentially starting from B1.

• Multi-Branch Monitoring Capability: Suitable for DC systems up to 1500VDC and capable of monitoring up to 30 branches.
• Flexible Parameter Configuration: After installation, users can configure communication parameters, including address, baud rate, and parity check mode.
• Adjustable Alarm Settings: Supports configuration of total insulation resistance threshold, branch insulation resistance alarm threshold, total leakage current threshold, and branch leakage current threshold.
• Branch Configuration Management: Supports setting the number of connected branches. The configured branch number must match the actual number of connected leakage current sensors; otherwise, the module will report an error.
• Remote Start/Stop Control: Equipped with remote insulation monitoring start/stop function. The default status after power-on is OFF, with the grounding switch K disconnected. The monitoring function can be remotely enabled or disabled through shorting the R and U terminals or via RS485 communication.
• Continuous DC Voltage Monitoring: After power-on, the PWR indicator lights up, and the module continuously monitors DC voltage within the range of 0~1500VDC. The DC voltage value can be read in real time regardless of operating or standby status.
• Wide Applications: Suitable for DC IT systems including DC charging systems, photovoltaic systems, energy storage systems, DC power grids, and DC distribution systems.

How does branch-level monitoring find the faulty branch?

A standard insulation monitor tells you that insulation has dropped somewhere on the DC bus. In a container or plant with many rack strings, the next question is which branch. With the GYDCG-MBC, each branch cable pair passes through a GYLCS leakage current sensor, and the main module reports the positive-to-ground and negative-to-ground resistance and the leakage current of every branch. The faulty branch can then be identified while the system keeps running, instead of disconnecting branches one by one. The principle is compared with other methods in our DC ground fault detection guide.

Installation notes from the documentation

• Connect the sensors in order, starting from channel B1.
• Match the arrow on each sensor to the direction of cable current.
• Set the number of branches to the number of sensors actually connected, or the module reports an error.

Frequently asked questions

How many branches can one GYDCG-MBC monitor?

Up to 30 branches, on channels B1 to B30.

What voltage and resistance ranges does it cover?

DC systems up to 1500VDC. Total system insulation resistance is monitored up to a range of 0KΩ ~ 10MΩ, and branch insulation resistance up to 0KΩ ~ 2MΩ.

Which monitoring methods are supported?

You can select the unbalanced bridge method for insulation resistance monitoring or the balanced bridge method for leakage current monitoring.

Does a large ground capacitance affect it?

The module adapts to ground capacitance automatically. The larger the capacitance, the longer the monitoring cycle, and the maximum cycle can be customized to customer requirements.

Related guide

• Insulation monitoring for battery energy storage systems: 1500 V BESS guide

Technical support and certificates

Gongyuan (Suzhou Gongyuan Automation Technology Co., Ltd.) has focused on insulation monitoring since 2017 and operates a quality management system built to the ISO 9001:2015 standard. For a multi-branch project, send the number of branches, DC voltage and communication needs through our contact page. Certificates and test reports are listed on the Certifications page. Specifications on this page come from Gongyuan’s product documentation; please confirm the final model and options with our engineers before ordering.