Since water is conductive when passing through it, ordinary meggers cannot measure accurately and the measured resistance is very low.
The insulation classification of the double water internally cooled generator is measured
1. The situation measured with a special dual-water megger is: water enters the stator through the coil; the insulation resistance should be greater than 30KΩ; The water-cooled engine should be tested with flowing water. The conductivity should not be higher than: 2.0 × 102 μS/m2 when the water temperature is 20°C. The stator coil is cleaned after the measurement.
If it is a water-cooled generator, a special water agitator should be used when measuring the insulation of the stator, and the water pipe part must be shielded and connected.
1. When measuring insulation, it is not necessary for water to pass through it. When there is noas water, the stator is qualified if measured with a megometer and above 2 M; when the water in the coil is not dried, it is measured with shielded wiring method by megohmmeter. After the water passes, it is measured with water. - Cooled motor insulation tester, and all are qualified above 6M.
2. The water collection ring and the external fixed cold water pipe are isolated by the connection flange.
3. Since the external fixed cold water pipe is grounded, what is protected is: the leakage current generated in the water after the megger is pressurized.
Model TQ-3-2. In 1969, Shanghai Electric Machinery Factory first designed and manufactured a 125,000 kilowatt internally cooled double steam turbine generator set. The machine adopted the latest international double internal cooling model. cooling method and high temperature appliedThe intermediate and high pressure reheating and other technologies are directly coupled and driven by the steam turbine, which has large overload capacity and fully meets the requirements of international IEC standards. It has the characteristics of high short circuit ratio, good stability for power grid, small size, light weight, low material consumption, simple system and convenient operation and maintenance. Currently, this product has been developed into a train of 50,000 to 300,000 kilowatts, with an apparent power of 62,500 to 353,000 kilowatts, an active power of 50,000 to 300,000 kilowatts, a voltage of 10,500 to 18,000 volts. , a current of 3,440 to 11,320 amps. and rotation speed of 3000 rpm, power factor is 0.8-0.85, frequency is 50 Hz, efficiency is 98.1-98.45%, stator weight is 52 to 157 tonsand the rotor weight is 18-57 tons. . It can be used for industrial and agricultural production as well as for lighting in large and medium-sized cities.