Power transformer is one of the most important operating equipment in power system. Its normal operation has a great impact on the safe operation of power grid. From the point of accident analysis, many accidents are unexpected accidents caused by the enlargement of local faults. But at present, the criterion of equipment operation depends on preventive test. Because of the long period of preventive test, the current preventive test project is insensitive to the developmental fault of insulation. As well as the development speed in a few days to weeks of local defects often can not be found in time, this kind of local defects in a few weeks or even shorter time to expand the accident caused by a larger proportion of transformer accident statistics. Therefore, on-line monitoring of transformers has become an important part of insulation diagnosis.

On the other hand, the current system reform of China's power system has put forward higher requirements for the reliability and economy of power transmission, that is, to build a transmission and distribution network with sufficient reliability level at the lowest cost. However, the periodic maintenance system formed for a long time can not meet such production objectives. In order to solve the thorny problems faced by power enterprises in the fierce market competition, such as how to improve reliability, how to effectively control maintenance costs, and how to reasonably prolong the service life of equipment, it has become inevitable to carry out condition-based maintenance for electrical equipment, especially transformers. Through real-time monitoring of the actual operation of high-voltage equipment, improving the diagnostic level of electrical equipment and achieving targeted maintenance, we can achieve the purpose of early fault prediction and avoidance of malignant accidents. In the current transformer on-line monitoring technology, oil-in-gas analysis (DGA) is one of the most mature, effective and popular technologies in the power sector. The oil-in-gas analysis method has been listed as the first of 32 pre-test items of oil-immersed transformer in the DL/T 596 pre-test regulation in 1996.

HYG-815Y transformer oil chromatographic on-line monitoring system (multi-component principle) is based on gas chromatography technology for on-line monitoring of dissolved multi-component gases in transformer oil. The system can detect on-line the content of dissolved H2, CO, CO2, CH4, C2H2, C2H4, C2H6 and other gases in transformer oil according to a certain period. The expert system is used to judge whether there are latent faults, whether they are overheating or discharge faults, and sound and light alarms are made according to the set alarm values. The on-line monitoring system can send each test result to the relevant personnel's mobile phone through the short message of the mobile phone, so as to understand the operation status of the transformer in time.

HYG-815Y system is composed of gas acquisition module, oil-gas separation module, gas detection and data acquisition module, spectrum analysis module and so on.

The gas acquisition module realizes the separation function of transformer oil and gas. In the oil-gas separation module, the sampling oil is separated by vacuum degassing device, and the gas flow is separated by chromatographic column. The separated gas is transformed from chemical signal to electrical signal in the chromatographic detection system. The gas signal is collected by the data acquisition module and uploaded to the background monitoring system through the communication port. The system can analyze and calculate the spectrum, and automatically calculate the concentration value of each gas according to the gas calibration data. According to the value of gas concentration, the fault diagnosis system can automatically diagnose the operation status of transformer by using the transformer fault diagnosis algorithm in the software system. If abnormal system is found, the type of internal fault of transformer can be diagnosed and maintenance suggestions are given.

Table: Model and Configuration of HYG-815Y Products

Product model

Product category

Detection of Gas Types

HYG-815Y

Multicomponent on-line monitoring

H2, CO, CO2, CH4, C2H2, C2H4, C2H6, micro-water, etc.

Ambient temperature and humidity (optional function)

1. Technical parameters

Power supply: 220V 50Hz AC power supply

Rated power: 800W

Cylinder carrier gas: 99.999% of high purity air, available locally

Carrier gas replacement: about three years (based on daily monitoring)

Degassing module life: more than eight years

Oil-gas equilibrium time: 10 minutes

Analysis cycle: minimum 1 hour, can be set arbitrarily

Calibration period: more than 2 years

Chromatographic column life: using periodic self-activation technology, service life is longer than 8 years

Detector life: more than eight years

Data storage cycle: 20 years

Working Environment Temperature: Transformer Oil Temperature Range: 15 80.

Temperature range of working environment: - 40 +70

Working relative humidity: 5%-95%, no condensation

Software Installation: Running on Win2000/XP Platform

Panel Indicator: There are two-color indicator lights on the panel inside the box.

Green-Power Supply, Red-Device Fault

Cabinet size: 750 (long)x 650 (wide)x 1200 (high) mm

Cabinet weight: 150 KG

Protection Level: IP65 or above

Measuring range of grounding current of iron core: 0.1mA~20A

Accuracy of current measurement: +0.1%

2. Technical characteristics

Oil extraction method: forced circulation, timely detection, no dead zone oil sample

Degassing mode: vacuum infinite degassing Technology

Detection Principle: Imported Gas Sensor

Types of measurement: H2, CO, CO2, CH4, C2H2, C2H4, C2H6, micro-water, etc.

Separation method: imported chromatographic column

Sampling mode: electromagnetic six-way valve injection

Temperature Control: Fuzzy PID Control

Calibration method: external calibration method, manual periodic calibration

Data Communication: RS485/GPRS Cable/Wireless Communication Options

Communication distance: RS485,2000 meters (communication between field device and background monitoring system)

Communication protocol: Compatible with substation automation system and dispatching automation system, it is convenient to realize remote transmission of information.

Network Protocol: Supporting TCP/IP Network Protocol, Supporting Remote Monitoring and Remote Maintenance

Alarm mode: on-site device light alarm; background software secondary sound/light alarm, mobile phone signal alarm, etc.

Fault diagnosis: IEC60599, national standard three-ratio method, two-ratio method, David triangle method, cubic diagram method, etc.

HYG-815Y Detection Index

Monitoring Indicators of Gas and Micro-water in Oil

Serial number

Gas

Minimum detection concentration

Detection range

check the accuracy

One

H2

1ppm

1-5000ppm

Those with (+10%) or 1 ppm in size

Two

CO

1ppm

1-5000ppm

+ 10%

Three

CO2

10ppm

10-10000ppm

+ 10%

Four

CH4

0.5ppm

0.5-4000ppm

Those with (+10%) or 1 ppm in size

Five

C2H6

0.1ppm

0.1-3000ppm

Those with (+10%) or 1 ppm in size

Six

C2H4

0.5ppm

0.5-4000ppm

Those with (+10%) or 1 ppm in size

Seven

C2H2

0.1ppm

0.1-2000ppm

Those with (+10%) or 1 ppm in size

Eight

Total hydrocarbon

0.1ppm

0.1-8000ppm

Those with (+10%) or 1 ppm in size

Nine

Micro water

1ppm

1-100ppm

Those with (+10%) or 1 ppm in size

Ten

oil temperature

-40-+180 C

+ 0.1 C

Temperature and humidity on-line monitoring indicators

Device name

Monitoring parameters

measuring range

measurement accuracy

Environmental Science

ambient temperature

- 20 ~80

+ 0.1%

Ambient humidity

0 ~ 100%RH

+ 0.1%

1. The detection sensitivity is high, and the minimum detection limit for dissolved C2H2 and C2H6 in oil can reach 0.1 ppm.

2. The original vacuum infinite degassing technology can measure any trace gas content in transformer oil.

3. Circulating oil extraction mode, no oil discharge, no pollution of oil, fast degassing speed.

4. It can detect more than seven kinds of gases and micro-water content in transformer oil, such as H2, CO, CO2, CH4, C2H2, C2H4, C2H6, etc. It can display spectrograms in real time on the back-end, and the original data such as spectrograms are completely open to users. The system has the function of self-inspection of the device. When the device fails, the light will be turned on and displayed on the background computer. When the cylinder pressure is insufficient, the device can alarm promptly through the mobile phone, prompting the relevant personnel to deal with it.

6. The system has two-level gas threshold alarm and growth rate alarm functions, alarm concentration and growth rate can be set arbitrarily.

7. Equipped with expert system for judging latent faults, the latest oil chromatographic fault diagnosis technology adopts IEC60599 standard, improved fuzzy three-ratio method, David triangle, cubic graphics and other methods, users can choose at will.

8. The monitoring results of each system are transmitted to the relevant personnel by short message in time (optional). There is no need for a person to check the data in the background, so that no one is on duty.

9. It has the function of querying historical data trend chart, displaying report format and printing, which is convenient to compare monitoring data vertically, and then analyze transformer operation situation and fault development trend.

10. Supporting TCP/IP network protocol, it can directly connect with user's MIS system, and has the function of web remote data browsing.

11. Support a variety of communication networking modes, compatible with the substation automation system or dispatching system of major manufacturers.

12. Referring to the national product standards of relay protection industry, the products have passed the EMC performance test of State Grid Company strictly.

13. The system is highly integrated. The grounding current with iron core and environmental temperature and humidity monitoring function can be optionally equipped in the components.