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Variable-speed drives and pulsing ground-fault location Pages  
The effect of harmonics from VFD’s on ground-fault protection Variable-speed drives use semiconductor components to rectify and invert voltage and current. To create an AC output, the internal DC…  
Conversion of a solidly grounded system into an HRG system Pages  
Why NGR’s require continuous monitoring The neutral-grounding resistor (NGR) is a critical element of a high-resistance-grounded (HRG) electrical power system. HRG systems always include…  
TN-S-/TT system Pages  
By the use of residual current monitoring systems, a message is given to the user before the shutdown threshold of an RCD is reached. RCMs (Residual Current Monitors) monitor residual currents in…  
Continuous availability, operational reliability and cost efficiency through permanent residual current monitoring Pages  
Comparison of the necessary insulation resistance measurements with an RCM-monitored electrical system The following section compares conventional DC insulation resistance measurement with the…  
How does residual current monitoring work? Pages  
All conductors of the outgoing circuit to be monitored (except the PE conductor) are routed through a measuring current transformer. In a fault-free system, the sum of all currents is equal to zero…  
Why residual current monitoring? Pages  
Comprehensive information Clear information centrally indicated on an LC display Transparency of all safety-related information through data transfer via bus systems and integration into…  
Signalling instead of switching – Residual current monitoring in earthed systems Pages  
In TN systems, the star point of the feeding transformers is connected to earth through a low impedance and the exposed conductive parts of the electrical installation are connected to the…  
IT system: Unearthed systems for maximum availability Pages  
As input to unearthed IT systems, either a transformer or an independent power source, such as a battery or a generator are used. Since no active conductor is connected to earth with a low…  
IT systems as reflected in the standards Pages  
Figure 13: The second fault in the IT system In accordance with IEC 60364-4-41:2017-03, subclause 411.6.4, after an initial fault occurs, the conditions for an automatic disconnection following a…  
Insulation resistance - testing, measuring, monitoring Pages  
During periodic tests the measurement of the insulation resistance is part of the measurements to be undertaken in accordance with DIN VDE 0105-100 (VDE 0105-100):2009-10. The insulation…  
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