CN104393576A - Low-voltage power distribution cabinet safety protection method - Google Patents

Abstract

The invention discloses a safety protection method for a low-voltage power distribution cabinet. When the upper water level sensor switch signal changes, the wireless low-voltage power distribution cabinet data collection terminal immediately sends an event to all intelligent residual current actions in the low-voltage power distribution cabinet after receiving the signal Protector, the intelligent residual current action protector controls the AC contactor coil to power off. When the temperature data is higher than the limit value, the data collection terminal of the wireless low-voltage power distribution cabinet will immediately send an event to the intelligent residual current action protector of the corresponding power supply circuit. The intelligent residual current action protector controls the power-off of the AC contactor coil, and at the same time, the data collection terminal of the wireless low-voltage power distribution cabinet sends this event to the server of the county bureau, and the real-time monitoring system module gives an alarm and synchronously sends a text message to the mobile phone of the equipment administrator. The invention solves the inconvenience caused by using the infrared thermometer for daily inspection to measure the temperature of the cables.

Description

A safety protection method for low-voltage power distribution cabinet

The patent application of the present invention is a divisional application of the invention title "an improved structure of safety protection device for low-voltage power distribution cabinet". The original application date is May 31, 2012, and the application number is 2012101800325.

technical field

The invention relates to a safety protection method for a low-voltage power distribution cabinet.

Background technique

At present, power supply companies have not considered the temperature monitoring and fault automatic disconnection isolation measures at the connection between the cable and the RTO fuse, and when the equipment is inspected every month, the safety regulations stipulate that direct contact with the cable is not allowed with hands, so the surface of the cable cannot be inspected temperature. If a certain line of a certain group of low-voltage cables is burned due to loose connection or overload and heat, resulting in a short circuit, it will affect the scrapping of this group of cables or the burning of equipment in the entire low-voltage power distribution cabinet. Power outages for users under the low-voltage outlets, most of which are all power outages for several groups of low-voltage outlets in the entire low-voltage power distribution cabinet to connect users. In addition, whenever there is a heavy rainstorm, the low-lying power distribution room often accumulates water, and it has also happened that the water flooded to the RTO fuse of the low-voltage outlet and burned the entire equipment in the low-voltage power distribution cabinet.

Contents of the invention

The technical problem to be solved by the present invention is to provide a safety protection method for low-voltage power distribution cabinets, which can realize temperature monitoring at the connection between low-voltage outgoing cables and RTO fuses, automatic disconnection and isolation of fault points, early warning of lower water levels and automatic disconnection of upper water levels The power supply for the lower part of the low-voltage distribution cabinet.

In order to solve the above technical problems, the present invention adopts the following technical solutions: a safety protection method for low-voltage power distribution cabinets. The low-voltage power distribution cabinet is fixedly installed with a lower water level sensor at a distance of 100mm from the ground, and an upper water level sensor is fixed at a distance of 200mm from the ground. Wireless The data collection terminal of the low-voltage power distribution cabinet receives the signals transmitted by the lower water level sensor and the upper water level sensor. When the switch signal of the lower water level sensor changes, the data collection terminal of the wireless low-voltage power distribution cabinet immediately transmits the signal to the county bureau server. The monitoring system module gives an early warning and sends a text message to the equipment administrator. When the switch signal of the upper water level sensor changes, the data collection terminal of the wireless low-voltage power distribution cabinet immediately sends the event to all the intelligent residual current action protectors in the low-voltage power distribution cabinet after receiving the signal , the intelligent residual current action protector controls the AC contactor coil to power off, and at the same time, the data collection terminal of the wireless low-voltage power distribution cabinet sends this event to the server of the county bureau. The low-voltage outgoing line of the power distribution cabinet is equipped with a contact temperature sensor on the conductor surface at the lower end of the fuse, and the wireless low-voltage power distribution cabinet data collection terminal receives the temperature signal transmitted by the contact temperature sensor and sets an upper limit for the transmitted temperature data. A limit value and a limit value, the limit value temperature is higher than the upper limit value temperature, when the temperature data is higher than the upper limit value, the wireless low-voltage power distribution cabinet data collection terminal sends an event to the real-time monitoring system module for early warning, and the real-time monitoring system The module sends a text message to the mobile phone of the equipment administrator; when the temperature data is higher than the limit value, the data collection terminal of the wireless low-voltage power distribution cabinet will immediately send an event to the intelligent residual current action protector of the corresponding power supply circuit, and the intelligent residual current action protector controls the AC The contactor coil is powered off, and the data collection terminal of the wireless low-voltage power distribution cabinet sends this event to the server of the county bureau. After the real-time monitoring system module alarms and synchronously sends a short message to the mobile phone of the equipment administrator, this event is sent according to the fixed-point ID number corresponding to the smart The residual current action protector ensures the disconnection and fault isolation of the power supply circuit, and does not affect the power supply of other normal power supply circuits in the same cabinet to low-voltage users.

The advantage of the present invention is: at present, the temperature monitoring of electric power enterprises is limited to the substation and the information room. Therefore, the present invention solves the inconvenience caused by using infrared thermometers to measure the temperature of cables during daily inspections, and when the cable When the surface temperature rises beyond the limit due to overload or loose connection, the faulty low-voltage circuit will be quickly and automatically isolated to prevent other low-voltage power supply circuits in the same cabinet from being forced to return. The principle of water level monitoring is simple, but its effect is value-for-money and the cost is light. At the same time, it also solves the accident of burning out the whole set of low-voltage power distribution equipment due to flooding of low-voltage outlet RTO fuses during heavy rain.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and specific embodiment:

Fig. 1 is a schematic block diagram of the present invention;

Fig. 2 is a wiring diagram of the present invention.

Detailed ways

In conjunction with Fig. 1 and Fig. 2, it is specifically described as an embodiment of an improved structure of a low-voltage power distribution cabinet safety protection device according to the present invention, including a low-voltage busbar 1, a fuse 2, a low-voltage user 3, a current transformer 11, and a zero-sequence current transformer 12 , 1#-4# contact temperature sensor 13, upper water level sensor 14, lower water level sensor 15, AC contactor 21, intelligent residual current action protector 22, temperature and water level transmitter 23, wireless low-voltage power distribution cabinet data collection terminal 24. County bureau server 31, SQL2005 database 32, data application analysis module 33, real-time monitoring system module 34, remote control module 35.

Among them, the low-voltage busbar, AC contactor, fuse, and low-voltage users are connected to form a low-voltage power supply unit; current transformers, zero-sequence current transformers, 1#-4# contact temperature sensors, upper water level sensors, and lower water level sensors form data acquisition Unit; data collection and transmission control unit composed of AC contactor, intelligent residual current action protector, temperature and water level transmitter, wireless low-voltage power distribution cabinet data collection terminal; county bureau server, SQL2005 database, data application analysis module, real-time monitoring system The module and the remote control module form the application system unit.

The low-voltage power supply unit is connected by low-voltage busbar, AC contactor contact system, fuse, and low-voltage users with three-phase three-wire (A, B, C), and the neutral line (N) is not connected to the AC contactor contact system and fuse , using a direct connection.

The data acquisition unit connects current transformers, zero-sequence current transformers, and intelligent residual current action protectors, and the intelligent residual current action protectors collect three-phase currents and zero-sequence current values; 1#-4# contact temperature sensors, The upper water level sensor, the lower water level sensor, and the temperature and water level transmitter are connected to collect the voltage signal of the contact temperature sensor and the switching data of the upper (lower) water level sensor. The data collection terminal of the electric cabinet conducts analysis, comparison and storage.

The data collection and transmission control unit is connected to the coil of the AC contactor through the intelligent residual current action protector; the intelligent residual current action protector, the temperature and water level transmitter, and the data collection terminal of the wireless low-voltage power distribution cabinet are connected by RS485 communication interface according to different protocols , the data collected in real time by the installation equipment is analyzed and compared in the terminal, and then the event is given, and then the event is returned to the intelligent residual current action protector through the data collection terminal of the wireless low-voltage power distribution cabinet, and the actuator sends commands to control the communication The contactor coil turns on (off) the power. The application system unit completes data exchange and command control by establishing a wireless network between the wireless low-voltage power distribution cabinet data collection terminal and the county bureau server; SQL2005 database, data application analysis module, real-time monitoring system module, remote Real-time data analysis, early warning, alarm and remote control operation are established between the control modules.

To monitor the temperature exceeding the limit and automatically cut off the power supply is to install a contact temperature sensor at the 50mm connection between the A, B and C phase RTO fuses and the low-voltage outlet cable, and install a contact sensor at the 50mm connection between the N phase, and use high temperature resistant nylon After the cable tie is fixed, a high-temperature resistant silicone rubber sheath is added to protect it, and it is used for real-time monitoring of the surface voltage signal of the low-voltage outgoing cable through a temperature and water level transmitter for digital conversion. When the monitoring temperature of one of the phases A, B, C, and N exceeds the upper limit compared with the terminal set value, the terminal sends an event to the real-time monitoring system module of the application system for early warning and sends a short message to the equipment administrator; if the surface temperature of the road When the limit of the set value of the terminal is exceeded, the terminal will immediately send an event to the intelligent residual current action protector of the corresponding power supply circuit. The action is disconnected to stop the power supply at the lower end. At the same time, the terminal sends this event to the server of the county bureau. After the real-time monitoring system module alarms and synchronously sends a short message to the mobile phone of the equipment administrator. This event is sent to the corresponding intelligent residual current action protector according to the fixed-point ID number to ensure the disconnection of the circuit power supply and fault isolation, without affecting the power supply of other normal power supply circuits in the same cabinet to low-voltage users.

When the water overflows to the upper water level sensor, the low-voltage outgoing line power supply in the low-voltage power distribution cabinet is automatically cut off. The lower water level sensor is fixedly installed at a distance of 100mm from the ground in the low-voltage power distribution cabinet, and the upper water level sensor is fixed at a distance of 200mm from the ground. Through the water level sensor switch After the signal is converted by the temperature and water level transmitter, it is sent to the data collection terminal of the wireless low-voltage power distribution cabinet, and the event is given by the terminal to control the intelligent residual current action protector to execute relevant instructions. When the switch signal of the lower water level sensor changes, the terminal immediately transmits the signal to the county bureau server via the wireless network after receiving the signal, and the real-time monitoring system module gives an early warning and sends a short message to the equipment administrator. If the switch signal of the upper water level sensor changes, the terminal will immediately send an event to all the intelligent residual current action protectors in the cabinet, and the executive element will cut off the power supply of the protector line package, so that the coil of the AC contactor is powered off, and the contacts of the AC contactor The system action disconnects and stops the power supply at the lower end. At the same time, the terminal sends this event to the server of the county bureau. After real-time monitoring of the system module alarm and synchronously sends a text message to the mobile phone of the equipment administrator.

The monitoring load exceeds the preset value and automatically cuts off the power supply by installing an integrated current transformer 200mm below the AC contactor of the low-voltage power distribution cabinet. The current transformer is connected to the intelligent residual current action protector through a USB interface to monitor the low-voltage power supply in real time The current value of phase A, B, and C of the circuit. When the measured current value is compared with the preset value of the internal discrimination element of the intelligent residual current action protector, the deviation is obtained, and then according to the nature of the deviation, the upper limit is exceeded, and an event is sent to the data collection terminal of the wireless low-voltage power distribution cabinet, which is transmitted through the wireless network To the county bureau server, the real-time monitoring system module will give an early warning and send a short message to the equipment administrator. If the limit is exceeded, the executive element will cut off the power supply of the protector line package, so that the coil of the AC contactor will be powered off, the contact system of the AC contactor will be disconnected to stop the power supply at the lower end, and at the same time send an event to the terminal, which will forward the event to the county The office server, through the real-time monitoring system module alarm and synchronously sends a short message to the mobile phone of the equipment administrator. This event only controls the intelligent residual current operating protector connected to this group of current transformers, and does not affect the normal operation of other intelligent residual current operating protectors in the same cabinet.

When the zero-sequence current value exceeds the preset value or the power supply circuit is automatically cut off when there is an electric shock, the zero-sequence current transformer is fixedly installed 200mm below the current transformer of the low-voltage power distribution cabinet, and the zero-sequence current value is collected in real time. The zero-sequence current transformer adopts The aviation plug is connected to the intelligent residual current action protector, and the data is detected by the intelligent residual current action protector to detect the zero-sequence current value. When the real-time collected zero-sequence current value exceeds the preset value, the intelligent residual current action protector sends an event to the actuator , the executive element disconnects the power supply of the protector line package to cut off the AC contactor coil, and the AC contactor contact system disconnects to stop the power supply at the lower end. At the same time, the event is sent to the terminal, and the terminal forwards the event to the county bureau server. Real-time monitoring system module alarms and synchronously sending text messages to the mobile phone of the equipment administrator.

The application system unit uses the wireless low-voltage power distribution cabinet data collection terminal to transmit the real-time data to the county bureau server through the wireless network, and then transfers it to the SQL2005 database. The data application analysis module performs calculation, analysis, and comparison, and then passes the results through real-time monitoring. The system modules are displayed. The remote control module uses man-machine dialogue to remotely control wireless low-voltage power distribution cabinet data collection terminal parameter settings, intelligent residual current action protector rated leakage current, overload preset value, opening (closing) gate, real-time call measurement data, remote For operations such as tests, instructions are sent by the server of the county bureau to the data collection terminal of the wireless low-voltage power distribution cabinet, and then the terminal sends corresponding events to the intelligent residual current action protector for execution.

The above is only a specific embodiment of the present invention, but the technical characteristics of the present invention are not limited thereto, any changes or modifications made by those skilled in the art within the field of the present invention are covered by the patent scope of the present invention among.

Claims (1)

1. A safety protection method for a low-voltage power distribution cabinet, characterized in that: the low-voltage power distribution cabinet is fixedly installed with a lower water level sensor at a distance of 100 mm from the ground, and an upper water level sensor is fixed at a distance of 200 mm from the ground, and a wireless low-voltage power distribution cabinet data collection terminal Receive the signals transmitted by the lower water level sensor and the upper water level sensor. When the switch signal of the lower water level sensor changes, the wireless low-voltage power distribution cabinet data collection terminal will immediately transmit the signal to the county bureau server, and the real-time monitoring system module will give an early warning and send a short message To the equipment administrator, when the switch signal of the upper water level sensor changes, the data collection terminal of the wireless low-voltage power distribution cabinet will immediately send an event to all the intelligent residual current action protectors in the low-voltage power distribution cabinet after receiving the signal. Control the power-off of the AC contactor coil, and at the same time, the wireless low-voltage power distribution cabinet data collection terminal sends this event to the county bureau server. A contact temperature sensor is installed on the conductor surface at the lower end of the fuse, and the data collection terminal of the wireless low-voltage power distribution cabinet receives the temperature signal transmitted by the contact temperature sensor and sets an upper limit value and a limit value for the transmitted temperature data, The limit value temperature is higher than the upper limit value temperature. When the temperature data is higher than the upper limit value, the data collection terminal of the wireless low-voltage power distribution cabinet sends an event to the real-time monitoring system module for early warning, and the real-time monitoring system module sends a short message to the equipment administrator Mobile phone; when the temperature data is higher than the limit value, the data collection terminal of the wireless low-voltage power distribution cabinet will immediately send an event to the intelligent residual current action protector of the corresponding power supply circuit, and the intelligent residual current action protector controls the AC contactor coil to power off, and at the same time The data collection terminal of the wireless low-voltage power distribution cabinet sends this event to the server of the county bureau. After the real-time monitoring system module alarms and synchronously sends a text message to the device administrator’s mobile phone, this event is sent to the corresponding intelligent residual current action protector according to the fixed-point ID number to ensure The disconnection and fault isolation of the power supply circuit will not affect the power supply of other normal power supply circuits in the same cabinet to low-voltage users.