According to the statistics of the fire department, electrical fires account for about one-third of all fire accidents in the country. There are multiple reasons for electrical fire accidents, such as: the wires being used for a long time without maintenance, and the insulation layer being aged and damaged; Improper electrical design, including users arbitrarily increasing loads, causing wire overload and heating, and aging and failure of wire insulation layer; Various man-made damages cause wire breakage, etc. The essence of these phenomena is that excessive residual current causes electrical fires, so it is necessary to monitor the residual current of the distribution circuit in real time.

The digital residual current transformer is a product designed to solve the problem of real-time monitoring of residual current in distribution circuits. It is installed at the Type I concentrator on the distribution transformer side or the Type II collector on the user side, and connected to the terminal through RS485 to access the electricity information acquisition system. This device is similar to an electricity meter. The terminal collects real-time residual current data, residual current curve data, phase and three-phase power outage events, residual current alarm events, etc. of the distribution circuit through the RS485 channel. The main station of the electricity information collection system communicates with the terminal through the GPRS channel to obtain the above relevant data, providing a basis for solving the problem of excessive residual current in the distribution circuit.

The digital residual current transformer is installed at the distribution transformer on the low-voltage side or at the specific user's location. According to the installation location, there are five types of products:

Structural accessories of residual current transformer products of different models:

Attention:

　　·Aviation plug (4 power cords, 2 residual current analog wires, 3 reserved wires); The transformer on the transformer side (three-way integrated) has three aviation plug sockets.

　　·Due to the fact that power outages are generally not allowed on the distribution transformer side, open type current transformers are used; Closed end current transformers are used at the user's location.

　　·Open installation does not require dismantling of the busbar and does not affect the normal use of electricity by customers.

Using an electricity information collection system to collect data from residual current monitoring devices, statistical analysis of residual current data in the substation area is conducted to provide a good solution for preventing damage to collection equipment and electric shock to personnel.