Insulation quality monitoring

In a formed coil system each individual coil is pre-formed. insulated and cured, and is made rigid before it is inserted into the slots. The dielectric qualities of the coil insulation are monitored closely during the process of coil formation to ensure the required quality. For procedure and acceptance norms see Section 11.4.9. 

Monitoring the quality of insulation of HT formed coils during manufacturing 9/227... 

The tests for insulation resistance and dielectric loss factor should, however, be carried out on a completed machine also with formed coils to establish reference data for field tests, as noted in Section 9.6. However, these tests on a completed machine with formed coils do not monitor the process quality of insulation. 

This is a test to monitor the quality and dielectric behaviour of the insulating system of high-voltage machines, 5 kV... 

Insulating materials and their properties Ageing of insulation Practices of insulation systems Procedure for vacuum pressure impregnation Maintenance of insulation Monitoring the quality of insulation of HT formed coils during manufacturing... 

Check electrical equipment regularly for sparks or arcing. These conditions can trigger spontaneous combustion of flammable gases or cause dust explosions. To prevent electrical equipment from contributing to fires (1) Conduct regular inspections of insulation resistance and monitor the quality of insulation layers. (2) Inspect and correct naked wires and metal contacts to prevent short circuit. (3) Install explosion-proof seals or isolated lighting fixtures, switches and protective devices. 

SECM can also be used to gain information about the quality of the insulation on the conical tips. An approach curve is obtained at the air/solution interface, where the solution contains a redox mediator such as Fe(CN)g . The potential sufficient to reduce Fe(CN)g is applied to the tip and the tip current is monitored as the tip is moved from air into the aqueous ferricyanide solution. Figure 6.3.4.5a shows the air/solution approach curve for a finite conical tip insulated with anodic paint. No current flows until the tip first enters the solution, where the current then rises sharply in an UME transient, which decays to a constant steady-state current value. This constant value is maintained as more of the tip is immersed in solution. Figure 6.3.4.5a indicates that the tip is completely insulated with only the very end of the tip uncovered. In contrast, a poorly insulated tip showed leaks along the sides as more of the tip is immersed into the solution (Figure 6.3.4.5b). The tip current increases stepwise as more of the tip enters the solution. This behavior is an indication of pinholes in the insulating film. 

Direct inspections are important from the point of view of heat supply security to customers. They require usage of specialized equipment to the location of network failures, leaks and control of a district heating networks. Infrared cameras and other devices, which are part of the resistive pulse or alarm systems, are used to analyze the quality of the insulation of heating networks. They enable ongoing monitoring of the state of the system components to prevent the occurrence of major accidents. 

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