何に留意すべき期間中、溶接のつなが変圧器、電圧60kVとしますのでご注意ください。▼

What should be noted during the welding of leads for transformers with a voltage of 60kV and above? When welding leads for transformers with a voltage of 60kV and above, the following precautions should be taken: Before welding the leads, it is essential to wrap the base of the leads to be welded with wet asbestos rope and cover the winding with tarpaulin. The welding flux should be prepared as needed, but the usage time should not exceed 8 hours. After welding, it is necessary to remove welding flux, oxide residue, insulation scorching, and any burrs. The welding area should be covered with shielding material to prevent local discharge. If […]

What impact does altitude have on the operation of transformers? In areas where the altitude does not exceed 1000 meters, transformers can operate without considering the altitude factor. However, in regions with altitudes above 1000 meters, transformers must take into account the impact of thin air on heat dissipation and the stability of external insulation materials. As a result, transformers used in areas with altitudes above 1000 meters must specify the actual altitude of the operating location in the contract. This is to enable the manufacturing plant to consider the temperature rise limits and the minimum air clearances for external insulation. Typically, manufacturers address the requirements of high-altitude areas by

What is the function of the safety vent of a transformer? The safety vent, commonly referred to as an explosion-proof tube in the power supply industry, is a traditional protective device that is rarely used in newly designed transformers. Its main function is to rapidly release a large amount of gas through the safety vent membrane (glass plate) when a fault occurs inside the transformer, thereby providing protection for the transformer. The safety vent works in coordination with a regular oil storage tank, with the upper space connected to the oil storage tank through a common pipe. This ensures that both the oil storage tank and the safety vent space

What are the characteristics of the three commonly used winding configurations in transformers? (1) Y-shaped winding characteristics: The Y-shaped winding has a winding current equal to the line current, with a larger wire cross-section, providing excellent mechanical strength. The winding voltage is equal to 1/√3 times the line voltage, resulting in fewer turns and insulation requirements. The filling factor of the conductor is large, enabling graded insulation. Due to the high filling factor, the inter-turn capacitance is higher, resulting in a uniform distribution of impulse voltage. Additionally, the neutral point can be grounded and used to achieve a four-wire system. The main drawback of this configuration is the absence of

How is the protection of the lightning arrester at the neutral point of the transformer carried out? For transformers operating in a system with an effectively grounded neutral point, if the neutral point is not grounded, a lightning arrester should be installed at the neutral point. Similarly, for transformers operating in a system with a non-grounded neutral point, consideration should also be given to adding a lightning arrester at the neutral point. If the neutral point is grounded through a surge arrester, in order to eliminate the overvoltage that may occur at the end of the surge arrester, it is possible to install a lightning arrester in parallel with the

How is the External Withstand Voltage Test conducted? The External Withstand Voltage Test is a one-minute AC high-voltage test conducted on the tested transformer, also known as the AC Withstand Voltage Test. This test is employed to assess the insulation performance between different winding sides and between windings and ground, specifically evaluating the main insulation of the transformer. Therefore, it is only applicable to fully insulated transformers. During the test, the different winding sides of the tested transformer are connected together, with one side subjected to voltage and the other side grounded, as illustrated in Figure 98-1. During the External Withstand Voltage Test, the circuit should be closed when the

What types of capacitive bushings are there? For voltage levels of 110kV and above, using oil-immersed bushings would result in excessively large dimensions. Therefore, it is necessary to employ solid insulation manufactured based on the principle of capacitive voltage division as the primary insulation, namely by using a capacitive core. Depending on the material and manufacturing method of the capacitive core, capacitive bushings are divided into two types: resin-impregnated paper (RIP) type and oil-impregnated paper (OIP) type. Resin-Impregnated Paper (RIP) Capacitive Bushing. Its capacitive core is formed by interleaving single-sided resin-impregnated paper and aluminum foils through a process of heating, pressing, and rolling. After curing through heating, the outer surface

How is the lightning arrester protection of the transformer carried out? The lightning arrester is the most crucial basic component for protecting power generation equipment and transmission and transformation equipment. It also forms the foundation for determining the insulation level of high-voltage electrical equipment. Installed in front of the transformer, the arrester mainly consists of a spark gap and a non-linear resistor (valve plate). When the overvoltage generated by lightning attacks the transformer, it first passes through the arrester. At this point, the spark gap of the arrester discharges, thereby limiting the overvoltage on the insulation of the transformer. During the discharge process, the non-linear resistor with good volt-ampere characteristics

What are the precautions for live oil filtration? (1) Throughout the entire process of live oil filtration and degassing, the gas relay circuit of the transformer must be connected to the signal circuit to prevent gas leakage and oil running in the pipeline, causing the oil switch to trip and resulting in a large-scale power outage. (2) The pipelines and joints connecting the oil filter machine and the transformer must be securely tied, with no occurrence of rupture, damage, or gas leakage. (3) For forced oil-cooled and water-cooled transformers, the connected cooler oil pump should not be started, as the excessive oil pump flow can cause the heater of the

How are the deviation values of transformer parameters and the parameters using peak values specified? The specifications for evaluating the performance parameters of transformers are determined by technical conditions, and each standard value has corresponding deviation values, which can be categorized into several types: (1) Parameters with only a lower limit specified, without an upper limit, where larger values are better: a.Absorption ratio, insulation resistance; b. Distance between bushings with voltage; c. Insulation withstand capability; d. Local discharge test time and frequency, AC withstand voltage test time and frequency; e. Electrode surface; f. Number of impulse short-circuit tests; g. Number of impact tests; h. Electrical and mechanical lifespan of on-load