By Sunny | 19 March 2020 | 0 Comments

Detection Method of Transformer Core Fault

The general test methods for transformer core faults are as follows:

1.Clamp-type ammeter method (on-line measurement). The clamp-type ammeter method can accurately and uninterruptedly test the multi-point grounding fault of iron core for transformer with external lead. The grounding lead current should be measured regularly every year. The general current should be below 100 mA. If it is greater than this value, the monitoring should be strengthened. After the transformer is put into operation, the resistance of grounding wire is continuously measured several times as the initial value. If the initial value itself is large, it means that the transformer itself is caused by the large leakage of magnetic field. The fault-free grounding point can be considered if the difference between the measured values is not large. If the grounding wire current is greater than 1 ampere and increases more than the initial value, it may be low resistance grounding or metal grounding fault, which should be handled in time.

2. Chromatographic analysis (electrified oil extraction). Sampling and chromatographic analysis showed that if the total hydrocarbons increased significantly and methane and ethylene were the main components of the gas, while carbon monoxide and carbon dioxide changed little or basically unchanged compared with the past, it could be judged as overheating of bare metal, which may be due to multi-point grounding of iron core or damage of dimension margin between silicon steel sheets. If acetylene occurs in the total hydrocarbons mentioned above, it is likely that the unstable iron core will be grounded at multiple points.
3. Insulation resistance method (blackout test). The resistance between the core and the outer shell is measured by 2500 voltmeter. The insulation resistance is above 200 MHz, which shows that the core is well insulated. If the shaking meter indicates that the core is connected with the outer shell, the resistance between the core and the outer shell can be measured by an ohmmeter instead. If the measuring value is 200-400 ohms, it shows that the core has high resistance grounding points, and the transformer needs to be treated for multi-point grounding fault. If the measuring value is more than 1000 ohms, the current flowing through the ground wire is small and it is difficult to eliminate the fault, so it can not be handled and can continue to run regularly. On-line monitoring, such as clamp-type ammeter method (with external lead of iron core), oil chromatographic analysis method, should be processed after anomaly is found; if the measurement value is 1-2 Euros, it is judged that there is a metal grounding point in the iron core, and the transformer must be processed.
Leilang-Electric is located in Shanghai,China.We are specialized in manufacturing all kind of low voltage transformer,three phase transformer,single phase transformer, variac transformer,voltage stabilizer, ac stabilizer,power regulator, reactor, etc.
If any question about power supply for the equipments,
just feel free to tell us, we will provide the best solutions to you within 24 hours.
Take knowledge of us by more stories: http://www.leilang-electric.com
Where can you buy our products: https://shleilang.en.alibaba.com
How can you contact us for more details?

If any question about power supply for the equipments,
just feel free to tell us, we will provide the best solutions to you within 24 hours.
Take knowledge of us by more stories: http://www.leilang-electric.com
Where can you buy our products: https://shleilang.en.alibaba.com
How can you contact us for more details?
Tel.: +86 21 59585699
Mob /Skype/Wechat: +86 181 1725 4552
WhatsApp+86 182 2450 3809
Mail: sales2@leilang-electric.com



 

Leave a Reply

Your email address will not be published.Required fields are marked. *
Name
E-mail
Content
Verification code
ver_code
POPULAR BLOG