The DC Relay Protection Measurement and Control Device (DCR150 Series) is designed for protection, measurement, and control of urban rail transit DC traction power supply systems. The device provides protection and monitoring for DC system components, including incoming/outgoing lines, feeder circuits, frame leakage systems, and rail potential. It is suitable for various urban rail systems such as metros, trams, intercity railways, and trolleybuses, and supports DC overhead contact lines at all voltage levels.