Gas protection acts as an internal fault monitor, detecting "health issues" inside the oil tank. When problems occur, gases begin to circulate, prompting the protection system to take action and determine whether a fault has occurred.
1.Working Principle
When a fault occurs inside the transformer, the fault current and the ignited electric arc cause the transformer's oil and insulation materials to decompose, releasing gases. These gases flow through the oil and the gas channel to the upper part of the oil conservator, triggering the gas protection to act and send a signal: "Attention-there is an internal problem in the transformer."
2.Protection Scope
Phase-to-phase short circuits
Inter-turn short circuits
Winding-to-core or casing short circuits
Iron core faults
Oil level drop or oil leakage
Poor contact in tap changers or poorly soldered wiring
3.Advantages and Disadvantages
Gas protection is simple, fast-acting, and highly sensitive. It can detect all sorts of short-circuit faults inside the transformer's oil tank, and even warn you about small issues that differential protection might miss.
Gas protection only detects internal faults. It cannot detect external faults, like those on the bushings or outgoing lines. Therefore, it cannot serve as the sole protection. Besides, it has poor resistance to external interference. For example, it may malfunction during an earthquake.
Differential protection, also known as longitudinal differential protection, is the "super bodyguard" for transformers. It constantly monitors the condition of windings, bushings, and outgoing lines, ensuring that no unqualified external component affects system safety.
1.Working Principle
Differential protection determines if a fault has occurred by calculating the current difference on each side of the transformer. If an abnormal current appears on one side, the differential protection acts quickly to disconnect the faulty section.
2.Protection Scope
Multi-phase short circuits occurring in outgoing lines and windings
Severe single-phase inter-turn short circuits
Ground faults in high-current grounding systems
3.Advantages and Disadvantages
Differential protection can quickly and effectively isolate faults. And if wired correctly and debugged properly, it rarely malfunctions.
Differential protection is not sensitive enough to some minor inter-turn short circuits inside the transformer. Therefore, for these minor issues, it may not react. Gas protection will then step in to alert it.
The transformers of VKE adopt the perfect combination of gas protection and differential protection. This setup not only precisely monitors subtle internal faults but also effectively guards against external electrical issues. The two complement each other, providing comprehensive and reliable safety protection for the power system.