Thermal compensation in nonlinear circuits to enhance input dynamic range in analog optical fiber links for high current short circuit test

摘要

This paper introduces an analog fiber optic communication system for transporting signals in a high power laboratory. The basic process involves converting the test signals in the range of kilovolts (kV) and kiloamps (kA) into signals ranging from 200 millivolts (mV) to 200 volts (V). After modulation, the signals are are transmitted by a fiber optic transceiver from the testing zone to an analog receiver located in a control room. Nonlinear compensation techniques have been used to limit the voltage range at the input of optical fiber links. However, nonlinear compensation introduces linearity errors and gain thermal drift. Measuring systems based on an optical fiber transmitter-receiver pair are used in mid-voltage testing laboratories where aggressive electromagnetic interference (EMI) environments are a limitation for using conventional cabling. In this paper the application of a nonlinear compensation to improve transient signal handling capabilities for the measuring system is presented, while maintaining low linearity errors and low gain thermal drift. This work demonstrates that the non-linear compensated optical fiber approach yields a unique, electrically isolated, lightning-proof analog data transmission system for remote measuring systems in the highly aggressive EMI environment of high-power test laboratories.