CN104634929A - Online monitor for transformer gas - Google Patents

Abstract

The invention discloses an online monitor for transformer gas. The online monitor comprises a monitoring circuit, wherein a signal acquisition unit in the monitoring circuit, an outer EEPROM unit, a clock circuit, a display unit and an interface circuit are respectively connected with a microprocessor ATmega32 which is connected with an upper computer through a communication unit circuit; the interface circuit comprises a keyboard interface and an alarm interface composed of an indicating lamp and a buzzer; the outer EEPROM is AT24C512; the clock circuit is a DS1302 chip; the signal acquisition unit comprises a TGS813 gas sensor which is used for transmitting a gas concentration signal, a gas sensor temperature signal and a heater temperature signal into an AD converter of the microprocessor after acquiring the gas concentration signal, the gas sensor temperature signal and the heater temperature signal; the display unit is an LCM12832ZK liquid crystal display and is in serial communication with an I/O port of the microprocessor; and the communication unit circuit is in serial communication with the upper computer through RS-485. The amount of chips is reduced, and the volume of a circuit board and a connecting line among all modules are beneficial to realization of automation of a control system and operation optimization of a power system.

Description

Transformer gas on-line computing model

Technical field

The present invention relates to a kind of monitoring device, especially transformer gas on-line computing model.

Background technology

Along with the development of modern technologies and the progress of society, what electric system also became becomes increasingly complex, also more and more higher to the requirement of electric system, thus, also more and more harsher to the requirement of protecting electrical power system.Transformer, as one of power equipment important in electric system, also causes people more and more to pay attention to its protection, and the monitoring of Gas in Oil of Transformer is exactly wherein one.Through development for many years, develop into modern online monitoring from the monitoring of traditional off-line type to the monitoring of oil dissolved gas, it is applied in production and has obtained certain achievement.The running status of transformer can be divided into normal condition and abnomal condition.Normal condition just refer to transformer usually, running status safely, abnomal condition refers to that transformer is owing to having potential faults or having fault and can not run normally, safely or state out of service.Many faults of transformer or potential faults can pass through the reacting condition of the composition of oil dissolved gas and the content of various composition out.。As can be seen here, Gas in Oil of Transformer is monitored, and arrange transformer and electric system reasonably to run according to the result of monitoring or overhaul to be one of the important measures improving power supply reliability, security and economy., in power industry, the on-Line Monitor Device of transformer is applied to some extent.It seems at present, mostly these equipment are only to carry out initial analysis for oil dissolved gas, and to other state and fault, as the faults such as local pyrexia, multipoint earthing, shelf depreciation can not realize Real-Time Monitoring, say nothing of and adjust in real time relevant operational factor.

Summary of the invention

The technical matters that the application will solve overcomes above-mentioned defect, provides a kind of transformer gas on-line computing model.

For solving the problems of the technologies described above, the technical scheme of employing is:

Transformer gas on-line computing model, comprise observation circuit, signal gathering unit in observation circuit, outside EEPROM unit, clock circuit, display unit, interface circuit connect microprocessor ATmega32 respectively, and microprocessor connects host computer by communication unit circuit; The remote alarm interface that interface circuit comprises keyboard interface, is made up of pilot lamp and hummer, outside EEPROM is AT24C512, clock circuit adopts DS1302 chip, signal gathering unit comprises TGS813 gas sensor, for being sent to after gathering gas concentration signal, gas sensor temperature signal and heter temperature signal in the AD converter in microprocessor, display unit is LCMl2832ZK liquid crystal display, and carry out serial communication with the I/O mouth of microprocessor, adopt RS-485 serial communication between communication unit circuit and host computer.

The invention has the beneficial effects as follows: decrease number of chips, turn reduce the on line between the volume of circuit board and each module.For the design of circuit board and the anti-interference of device, there is great meaning.Utilize the communication module in Atmega32, can realize very easily and communication between other control device or upper level control device, be conducive to realizing the optimization of the networking of whole protection system, the robotization of control system and Operation of Electric Systems.

Accompanying drawing explanation

Fig. 1 is the circuit structure diagram of this gas on-line monitor.

Embodiment

Transformer gas on-line computing model comprises and comprises observation circuit, has with lower unit: the collecting unit (non-electrical signal becomes electric signal) of (1) gas concentration signal, gas sensor temperature signal, heter temperature signal; (2) microprocessor unit (signal collected is processed and controls other unit and normally work); (3) outside EEPROM and clock circuit unit; (4) display unit (showing the concentration value of gas, rate of change, time and temperature etc.); (5) interface circuit unit: mainly comprise keyboard interface, remote alarm interface.Keyboard is information input interface, and this is required in the entire system.Remote alarm interface also has great role, although there has been Liquid Crystal Module, can show a lot of information, but suitably increases some pilot lamp hummers, can find out some important states of equipment easily; (6) communication unit (with other monitor carry out communication or with the communication of upper level pulpit).

In this device, the Atmega32 in the AVR single chip that microprocessor (MPU) is selected.Atmega32 is 8 AVR microprocessors of a high-performance, low-power consumption.Namely it have the function of traditional micro-control unit (MCU), and it is integrated with again many peripheral modules simultaneously.The peripheral hardware that this device is used comprises: 40 I/O pins, 8 10, tunnels analog to digital converter (ADC),

The SPI serial line interface and I2C Bus interface etc. of main frame/slave mode can be worked in.In this device, need the memory capacity of preserving a large amount of data and microprocessor Atmega32 limited, so be equipped with outside EEPROM to microprocessor, selected chip is 64K electricity erasable memorizer AT24C512.。The mode of synchronous serial can be adopted between DS1302 with single-chip microcomputer simply to carry out communicating and only need to use three mouth lines: (1) RES(resets) (2) I/O(data line) (3) SCLK (serial clock).The effect of signal gathering unit is adopted outer signals in Atmega32 exactly, and changes into data that Atmega32 can identify and put into temporary storage location and be supplied to for display unit or communication unit.The core parts of signal gathering unit are sensors, and its effect is exactly that the non-electric charge quantity signalling (gas concentration value (ppm)) of input is converted to electric signal (direct current 1 ~ 5 volt) corresponding with it, and it is first unit of whole device.Its work range and operating accuracy are directly connected to working range and the precision of whole device.During the working sensor of this device, except work measurement power supply, also need heating power supply.The operating voltage of this device and heating voltage are all 5V.After the concentration signal of gas, gas sensor temperature signal, heter temperature signal are converted to electric signal, be fed in the A/D module of Atmega32.Sensor selected by this device is the TGS813 gas sensor that Japanese Figaro company produces, and it is low to the sensitivity of noise gas, is mainly used in measuring the inflammable gass such as methane, propane, butane and hydrogen.Due to the structural reason of sensor itself, it is the result of the comprehensive response to various gas ingredients to the response results of gas.After the concentration signal of gas becomes electric signal in the sensor, the first via entered in analog to digital conversion (AD) module of ATmega32 by the PA0 mouth of ATmega32 through 240 Europe resistance is changed, and its transformation result puts into ADC

In data register (ADCL and ADCH).Sensor in gas sensor temperature signal collection circuit adopts three-wire system temperature compensation connected mode, via the Differential input circuit of amplifier interface chip composition, the temperature signal value collected is met the analog/digital conversion interface PA1 (ADC1) of Atmega32, realize the data acquisition to temperature, heter temperature signal acquisition circuit have employed the same design with gas sensor temperature signal collection circuit, just the temperature signal value collected is received the analog/digital conversion interface PA2 (ADC2) of Atmega32.The display unit of this device uses the I/O of Atmega32 directly to carry out serial communication with peripheral display, and display selects LCMl2832ZK character mode lcd.Select four to touch composition keyboard, use Independent keys interface.These four buttons are upper and lower, ESC and SET.No matter be the data communication of microprocessor and peripheral hardware or the communication of whole device and host computer, use be all serial port.The data communication side one of microprocessor and peripheral hardware uses SPI serial ports another uses I2C serial ports.The communication of whole device and host computer adopts RS-485 communication network.

Claims (1)

1. transformer gas on-line computing model, it is characterized in that: comprise observation circuit, signal gathering unit in observation circuit, outside EEPROM unit, clock circuit, display unit, interface circuit connect microprocessor ATmega32 respectively, and microprocessor connects host computer by communication unit circuit; The remote alarm interface that interface circuit comprises keyboard interface, is made up of pilot lamp and hummer, outside EEPROM is AT24C512, clock circuit adopts DS1302 chip, signal gathering unit comprises TGS813 gas sensor, for being sent to after gathering gas concentration signal, gas sensor temperature signal and heter temperature signal in the AD converter in microprocessor, display unit is LCMl2832ZK liquid crystal display, and carry out serial communication with the I/O mouth of microprocessor, adopt RS-485 serial communication between communication unit circuit and host computer.