CN103401313A - Intelligent monitoring system of low-voltage electric cabinet - Google Patents

Abstract

The invention relates to an intelligent monitoring system for a low-voltage electric control cabinet, which belongs to the field of low-voltage power supply regulation and automatic control. Its signal acquisition circuit includes: a temperature sensor attached to the joint of the main power supply cable, and the digital voltage signal of the temperature sensor is output to the single-chip microcomputer; The digital voltage signal is output to the single-chip microcomputer; the power supply control output circuit accepts the control signal of the single-chip microcomputer, and its circuit breaker controls the on-off of the main power supply circuit; the communication interface of the single-chip microcomputer is connected with a network transmission that converts the logic standard of the serial port of the single-chip computer into the logical standard of the Ethernet interface module. The invention uses the microprocessor as the data acquisition and control execution terminal to complete the acquisition and processing of power supply operation and cable joint temperature signals, and can transmit the acquisition signals to the central control room through the Internet, and at the same time accept the information sent by the central control room Control commands to realize remote centralized measurement and control.

Description

Low-voltage electric control cabinet intelligent monitoring system

technical field

The invention relates to an intelligent monitoring system for a low-voltage electric control cabinet based on Internet of Things technology, belonging to the field of low-voltage power supply regulation and automatic control.

Background technique

Electric control cabinets with low and medium capacity are common power supply control devices, and are mainly used for small and medium-sized power consumers, such as residential buildings, enterprises and institutions, etc. The maintenance and use of these equipments mostly use electricians to carry out manual inspections. The inspections are often not timely, and abnormal situations cannot be found and checked in a timely manner, and sometimes the equipment is in an unattended operation state. When problems such as the increase of electricity load and partial oxidation of cable joints occur, the heat generation of the cable joints will increase, which can easily cause fires. Due to the problem of labor costs, it is unrealistic, untimely, and unobjective to invest a lot of manpower in management and maintenance. There are many devices for monitoring circuit parameters on the market. They are relatively complicated to install and large in size, and most of them are non-standard special devices. It is not suitable for the above-mentioned enterprises and institutions to use.

Contents of the invention

The present invention aims to solve the above-mentioned problems in the existing low-voltage power supply monitoring, and provides an intelligent monitoring system for low-voltage electric control cabinets that can realize centralized real-time monitoring of the safe operation of each electric control cabinet terminal.

The technical solution adopted by the present invention to solve the problem is:

An intelligent monitoring system for a low-voltage electric control cabinet, including a single-chip microcomputer, a signal acquisition circuit, and a power supply control output circuit. The signal acquisition circuit is: (i) a temperature sensor attached to the joint of the main power supply cable, and the digital voltage of the temperature sensor The signal output terminal is connected to the signal input interface of the single-chip microcomputer; (ii) a voltage transformer and a current transformer arranged on the main power supply cable, and the signal output terminals of the voltage transformer and the current transformer pass through the effective value conversion circuit and The signal input interface of the single-chip microcomputer is connected; the signal input end of the described power supply control output circuit is connected with the signal output interface of the single-chip microcomputer, and the power supply control output circuit is provided with a circuit breaker for controlling the on-off of the main power supply circuit; the communication interface of the single-chip microcomputer is connected with The network transmission module converts the logic standard of the serial port of the single chip microcomputer into the logic standard of the Ethernet interface.

The present invention adopts the above-mentioned technical scheme, it uses the microprocessor as the data acquisition and control execution terminal to complete the acquisition and processing of the power supply operation and the temperature signal of the cable joint, and can transmit the acquisition signal to the central control room through the Internet, and at the same time Accept the control instructions sent by the central control room to realize remote centralized measurement and control.

The further technical scheme of the present invention can also be:

The single-chip microcomputer is a microprocessor 89C52.

The temperature sensor is an integrated temperature sensor DS18B20.

The effective value conversion circuit is a multi-channel effective value conversion circuit with AD637, CD4051 and A/D converter as the core, and the A/D converter outputs the digital voltage signal to the P2 interface of the microprocessor 89C52.

The power supply control output circuit is composed of a circuit breaker J1 and a relay drive circuit centered on a relay J2 and an internal photocoupler.

Described network transmission module is based on network database MS SQL_server, adopts transmission protocol TCP and ICMP, TELNET to communicate through Ethernet link.

The human-machine interface P0 of the microprocessor 89C52 is connected with a keyboard for parameter preset input, the P3.0-P3.6 interface of the microprocessor 89C52 is connected with an LED display module for display output, and the P1 of the microprocessor 89C52 .4-P1.6 interface is connected with a telephone alarm circuit.

The telephone alarm circuit is composed of telephone module HT9200A and integrated audio amplifier circuit LM386.

Compared with the prior art, the outstanding effect of the present invention is: the monitoring host part is integrated in the electric control cabinet, the installation is simple, the cost is low, and the volume is small. An organic whole can be integrated based on the Internet of Things interconnection, and the central control room can realize centralized real-time monitoring of the safe operation of each electric control cabinet terminal, and truly realize the purpose of unattended safe power consumption.

Instructions attached

Fig. 1 is a system block diagram of the present invention.

FIG. 2 is a schematic diagram of a signal acquisition circuit according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of an effective value conversion circuit according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a power supply control output circuit according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of the telephone alarm circuit of the present invention.

Fig. 6 is a schematic diagram of the system of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the examples, and the purpose is only to better understand the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

Referring to Figure 1, each monitoring unit in the intelligent monitoring system of the low-voltage electric control cabinet is integrated in the electric control cabinet. The single-chip microcomputer used as the data acquisition and control execution terminal adopts the microprocessor 89C52, and the P1.0-P1 of the microprocessor 89C52. 2 The input interface receives the digital voltage signal sent by the temperature sensor, the P2 input interface of the microprocessor 89C52 receives the digital voltage signal sent by the effective value conversion circuit of the voltage and current transformer; the P3.7 output interface of the microprocessor 89C52 is connected to the power supply control output circuit The control signal input terminal of the microprocessor 89C52 is connected with a network transmission module that converts the logic standard of the serial port into the logic standard of the Ethernet interface. The network transmission module is based on the network database MS SQL_server, and adopts the transmission protocols TCP, ICMP, and TELNET Communication via Ethernet link; the man-machine interface P0 of the microprocessor 89C52 is connected with a keyboard for parameter preset input; the P3.0-P3.6 interface of the microprocessor 89C52 is connected with an LED display module for display output; The P1.4-P1.6 interface of the processor 89C52 is connected with a telephone alarm circuit.

See Figure 2, the signal acquisition includes two parts, one is: at the joints of three-phase power supply cables A, B, and C in the electric control cabinet, an integrated temperature sensor DS18B20 is respectively attached to measure the temperature change at the cable joint, and the electric control cabinet The normal power supply parameters in the cabinet are: three-phase power supply voltage 380V, current 100A, the change of cable joint temperature and the change of current form a quadratic function relationship. Each of the three DS18B20 converts the change parameters of the cable joint temperature into digital voltage signals through its built-in conditioning circuit, and then sends them to the microprocessor 89C52 through the P1.0, P1.1, and P1.2 interfaces of the microprocessor 89C52; The second is: arrange voltage transformers VHG1, VHG2, VHG3 and current transformers IHG1, IHG2, IHG3 on the three-phase power supply cables A, B, and C respectively, and the voltage transformers and current transformers input the monitored voltage and current signals To the effective value conversion circuit, and then the digital voltage signal is sent to the microprocessor 89C52 by the effective value conversion circuit.

Referring to Figure 3, the effective value conversion circuit is a multi-channel effective value conversion circuit with AD637, CD4051 and A/D converter as the core. The A/D converter converts the voltage and current signals monitored by the voltage transformer and current transformer A corresponding digital voltage signal is output to the P2 interface of the microprocessor 89C52.

Referring to Fig. 4, the power supply control output circuit in this embodiment is composed of a large-capacity circuit breaker J1 and its drive circuit, and the main contacts J1-1, J1-2, and J1-3 of the circuit breaker J1 control the main power supply circuit. Break (see Figure 2), that is to complete the opening and closing instructions issued by the microprocessor 89C52.

Referring to Fig. 5, the telephone alarm circuit in this embodiment is composed of a telephone module HT9200A and an integrated audio power amplifier circuit LM386, and sends telephone alarm information through a telephone line.

Referring to Figure 6, the system operation is divided into two parts: data preparation stage and online monitoring operation.

The data preparation phase includes the following steps:

① Use the system human-machine interface to input system standard reference parameters, such as voltage and current range, normal temperature of cable joints and over-limit temperature.

②Set or modify the initial parameters of the system operation.

③ Give the measurement error system compensation amount.

The online operation phase includes the following steps:

① After the data preparation stage, start the system and put it into operation.

②According to the comparison between the parameters obtained by the data acquisition part and the system standard parameters, a prompt or alarm signal is generated, and a self-rescue command is issued in an emergency (such as: when the temperature rise of the cable joint part exceeds the maximum threshold, cut off the power supply).

③On-line communication with the center through the Internet, transmit local measurement data to the center, and receive remote control instructions from the center at the same time.

④The client can install data viewing program software on any networked computer, as long as it can communicate with the console software system, it can read the data of the console and observe the real-time changes of the data. In this way, an organic whole is integrated through interconnection to realize truly unattended and safe operation.

Claims (8)

1. A low-voltage electric control cabinet intelligent monitoring system, comprising a single-chip microcomputer, signal acquisition circuit, power supply control output circuit, is characterized in that: a. The signal acquisition circuit is: (i) a temperature sensor attached to the joint of the main power supply cable, the digital voltage signal output terminal of the temperature sensor is connected to the signal input interface of the single-chip microcomputer; (ii) the voltage set on the main power supply cable A transformer and a current transformer, the signal output terminals of the voltage transformer and the current transformer are connected to the signal input interface of the single-chip microcomputer through an effective value conversion circuit; b. The signal input terminal of the power supply control output circuit is connected to the signal output interface of the single-chip microcomputer, and the power supply control output circuit is provided with a circuit breaker for controlling the on-off of the main power supply circuit; c. The communication interface of the single-chip microcomputer is connected with a network transmission module that converts the logical standard of the serial port of the single-chip microcomputer into the logical standard of the Ethernet interface. 2. The intelligent monitoring system of the low-voltage electric control cabinet according to claim 1, wherein the single-chip microcomputer is a microprocessor 89C52. 3. The intelligent monitoring system of the low-voltage electric control cabinet according to claim 1, wherein the temperature sensor is an integrated temperature sensor DS18B20. 4. The low-voltage electric control cabinet intelligent monitoring system according to claim 1, wherein the effective value conversion circuit is a multi-channel effective value conversion circuit with AD637, CD4051 and A/D converter as the core, A/D The D converter outputs the digital voltage signal to the P2 interface of the microprocessor 89C52. 5. The intelligent monitoring system of the low-voltage electric control cabinet according to claim 1, characterized in that, the power supply control output circuit is composed of a circuit breaker J1 and a relay drive circuit with a relay J2 and an internal photocoupler as the core. 6. the low-voltage electric control cabinet intelligent monitoring system according to claim 1, is characterized in that, described network transmission module is based on network database MS SQL_server, adopts transmission protocol TCP and ICMP, TELNET to communicate by Ethernet link. 7. The low-voltage electric control cabinet intelligent monitoring system according to claim 1 or 2, characterized in that, the human-machine interface P0 of the microprocessor 89C52 is connected with a keyboard for completing parameter preset input, and the P3 of the microprocessor 89C52 The .0-P3.6 interface is connected with an LED display module that completes the display output, and the P1.4-P1.6 interface of the microprocessor 89C52 is connected with a telephone alarm circuit. 8. The intelligent monitoring system of the low-voltage electric control cabinet according to claim 7, wherein the telephone alarm circuit is composed of a telephone module HT9200A and an integrated audio power amplifier circuit LM386.

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