Narrowband power line communication systems in the frequency range below 500 kHz may play an important role in building up a smart grid. In the last few years, many efforts have been made to characterize power line networks. However, there are few guidelines for translating these results into real-life applications, such as performance comparison of different NB-PLC systems with realistic channel conditions or investigation of PLC systems considering critical transmission channels. In this article we propose a topology-independent approach that covers the channel characterization, channel emulation, and performance evaluation of PLC systems with realistic channel conditions in the laboratory. A comparison of the modem performance measured under real channel conditions with the performance obtained with the emulated channel conditions verifies the accuracy of the channel emulation and the correctness of the proposed approach.