Open-phase fault monitoring system

An open-phase fault monitoring system, comprising a current monitoring unit, a relay communication unit, an energy extraction unit and a data processing unit, wherein:

• the current monitoring unit is configured to monitor multipath current signals, and comprises a cable current monitoring unit and a ground current monitoring unit, wherein the cable current monitoring unit is configured to monitor current flowing through a transformer cable, and the ground current monitoring unit is configured to monitor current flowing through a reverse current ground wire;
• each of the cable current monitoring unit and the ground current monitoring unit is an ring shape and is enclosed by two ferrite rings, where a center hole passes through a conductor to be measured and a magnetic ring air gap is machined on one of the ferrite rings to arrange a current monitoring unit circuit, wherein one terminal of each of the two ferrite rings is connected by a rotation shaft, and the other terminal thereof is provided with a connecting line interface where a connecting line is inserted to connect the current monitoring unit with the relay communication unit;
• the cable current monitoring unit and the ground current monitoring unit have a same circuit structure, both comprising two magnetic field sensing chips with tunnel junction magneto-resistive type, and the two magnetic field sensing chips with tunnel junction magneto-resistive type are correspondingly connect to two instrument amplifier circuits and two electric energy management modules of the current monitoring unit;
• a hardware part of the relay communication unit comprises a body, an antenna, a connecting line interface C, a battery compartment, a system restart key and a debugging interface;
• a circuit part of the relay communication unit is disposed on a printed circuit board, and comprises an MCU, a LORA module, an ADC a FLASH&WD, a GNSS&RTC module, a power management module of the relay communication unit and corresponding resistor-capacitor elements connected to the power management module;
• the antenna is disposed at the top of the body and connected to the LORA module and the GNSS&RTC module in the body of the relay communication unit;
• the LORA module enhances a signal via the antenna, and wirelessly sends data to the data processing unit for data processing;
• the GNSS&RTC module obtains time data from a satellite via the antenna to realize a data transceiving function of the relay communication unit;
• the connecting line interfaces C is disposed at the bottom of the body for a wired connection between the relay communication unit and the energy extraction unit and the current monitoring unit, and the connecting line interface C is connected to the printed circuit board and the power management module of the relay communication unit inside the body;
• and the battery compartment is disposed on a lateral side of the body, with a battery placed therein, and the battery is connected to the printed circuit board inside the body;
• the system restart key and the debugging interface are disposed on a lateral side of the body, the relay communication unit is refreshed by clicking the system restart key, and the relay communication unit is connected to a computer by the debugging interface, so as to modify and debug a program of the relay communication unit;
• the MCU of the relay communication unit is used as a central control processing unit and connected to ADC peripheral, the ADC converts the transmitted analog signal into a digital signal, and multipath analog signals is obtained in a short time;
• the FLASH&WD stores the data obtained and converted by the ADC, and the data is written into the FLASH&WD after being processed by the MCU, so that the past data is queried when the open-phase fault monitoring system is failed;
• the LORA module is connected to the MCU on the printed circuit board to realize a function of data wireless communication, and a working condition of the LORA module is controlled by the MCU to realize a continuous or intermittent data transmission to an industrial personal computer;
• the GNSS&RTC realizes a time calibration by a connection with the MCU to provide accurate moment signals, and calibrates a system clock continuously or intermittently;
• the energy extraction unit comprises two independent groups of magnetic ring for obtaining electrical energy based on induction principle, corresponding connecting circuits and a connecting line interface D;
• the inductive electromagnetic ring is wound with a coil, an outlet terminal of the coil is connected to an input terminal of the printed circuit board, and a rectifier bridge composed of capacitors is arranged on the printed circuit board;
• the rectifier bridge comprises two input terminals connected to two terminals of the coil respectively and an output terminal connected to an input terminal of a voltage regulator chip, and an output terminal of the voltage regulator chip outputs via the connecting line interface D;
• and the energy extraction unit obtains electric energy and supplies power to the current monitoring unit and the relay communication unit;
• and
• the data processing unit wirelessly receives information sent by the relay communication unit to perform a data analysis, and comprises the industrial personal computer, a relay and a LORA receiving device;
• the industrial personal computer is in wired connection the relay by a USB serial port, and directly connected to the LORA receiving device by a USB serial port;
• the industrial personal computer receives current data sent by the LORA module in the relay communication unit by the LORA receiving device, and the current data is directly read by the industrial personal computer by the USB serial port with a serial communication mode;
• the industrial personal computer judges phase opening based on the current data and controls the output of the relay.