high and high
For an insulating material dielectric strength and dielectric loss should be respectively
For an insulating material, the dielectric strength should be high to withstand high voltages without breaking down. Conversely, the dielectric loss should be low to minimize energy loss due to internal friction within the material when subjected to an electric field.
dielectric strength is tested by transformer dielectric strength oil testing machine. at first, oil which is to be tested is pour near the two electrode. both the electrode should be dipped in oil . then adjust the distance between the electrode .now start the machine.when a sound came from machine then note down the dielectric strength of the oil.
They should be made from insulating material.
d. Dialtetric Strength
The resistance of a dielectric material should ideally be very high, approaching infinity. This is because dielectric materials are insulators and used to prevent the flow of electrical current. A high resistance ensures that the dielectric can effectively store electric charge without allowing current to pass through.
When you say BDV you might mean the dielectric strength of transformer oil. A new transformer oil should have at lest a dielectric strength of 39 KV. from a British standard.Transformer oils used are normally tested using ASTM D877-82 with the KV strength tester using 1" electrodes spaced 0.1" apart and the test voltage increased at 3,000 volts/min until it breaks down. The average Kv obtained after 8 trials is considered the Oil dielectric strength.Using this test method,dielectric strength at 30 kv and above is considered good. Dielectric strength between 23 to 29Kvis considered usable, but requires filtering. Below 23 kv, the transformer oil should be replaced.Another method ASTM D18747-82 uses the small radius electrodes but spaced only .o4 inches. The test voltage is 500volts/min and increased until breakdown. The dielectric strength is still the average Kv obtained in 8 trials. The dielectric strength of 28-29Kv is considered good. Below 28 kv, the transformer oil is usable but requires filtering. The latter method is considered a better test method
A material is useful when it possesses the desired properties for a specific application or task, such as being strong, lightweight, flexible, or insulating. Additionally, the material should be readily available, cost-effective, and environmentally friendly to be considered useful.
Because electorn ionised the moisture content and evaporated. Every trial for the same sample moisture content get reduced which helps to improve dielectric strength a bit. But if the sample having very low dielerctric strength it should be thrown.
The main function of transformer oil is insulating and cooling of the transformer. It should have the following properties:High dielectric strengthLow viscosityFreedom from inorganic acids, alkali, and corrosive sulfurResistant to emulsificationFreedom from sludging under normal operationRapid settling of arc productsLow pour pointHigh flash point
The breakdown voltage test is used to evaluate the degree of impurity in insulating oils due to foreign particles, gas and water. It meets current regulations and is economically useful to protect electrical systems such as transformers and switches, as well as, medical and security systems from breakdowns. The main reason for such damage is the poor condition of the insulating oil. The oil tester is designed for continuous operation in the laboratory. This high performance instrument is characterized by the combination of extraordinary properties such as a test voltage up to 100 kV, clear breakdown detection and absolutely reliable measurement results. The TOP oil tester is the leading testing instrument for users in the electricity industry, in testing institutes and other industrial applications.
Because the gate terminal should highly resistive..silicon dioxide has high resistance and hence gate current is very very low...