Schwarzbeck NPLC 8500 Line Impedance Stabilization Network

The LISN NPLC 8500 has been designed especially for PLC measurements according to ITU-T G.9901. To determine the power spectral density of PRIME transceivers (PoweRline Intelligent Metering Evolution) the unsymmetrical voltage between a conductor and ground has to be measured within the frequency range of 3 kHz to 148 kHz.

The device under test has to be connected to the wing terminals at the front panel. Mains has to be connected to the wing terminals at the back panel of the LISN. Due to the high capacitance values built into this device very high leakage currents can occur (3.6 A at 50 Hz.) 

Thus the LISN has to be well connected to ground before putting the LISN into operation. Otherwise there is a risk of fatal injuries.

The NPLC 8500 must not be connected to a residual current operated circuit breaker by design because the RCD would break the circuit immediately due to the high leakage currents.

During powering up mains peaks up to 20 V could occur at the BNC port for up to 1 ms. This could damage measurement equipment which eventually is connected to the LISN. Hence connect the mains first and then connect the receiver.

Due to the variable possibilities of a hazard for man and material the NPLC 8500 may only put into operation by qualified personnel. Where necessary the operation by unauthorized persons may be prohibited with additional warning notes.

The LISN must not be covered to prevent overheating.

Principle Circuit Diagram of the NPLC 8500

Impedance at EuT terminals (BNC terminated with 50 Ω, mains terminals shorted)

Transmission EuT - BNC