Investigation of LED Lighting Performance in the Presence of Ripple Injection Load Control Signals

This paper presents the outcomes of laboratory evaluation of the performance of a sample of LED lighting systems (lamp/driver and dimmer combinations) in presence of audio frequency injection control (AFIC) signals used by electricity distribution system network service providers (DNSPs) for control of certain loads. The testing presented in this study has been undertaken in response to a significant number of customer complaints that have been received by DNSPs related to the performance of LED lighting systems with dimmers incorporated. In a number of cases, performance issues have been verified in the field to occur during periods where AFIC signaling voltages are present in the electricity distribution network. In order to determine the contributing factors that AFIC signaling may have on the performance of the LED lighting system, a light-based flicker evaluation testing system has been developed to investigate LED lighting system performance under controlled conditions. One of the main objectives of the study was to use light-based flicker indices to identify the effect on different combinations of LED lamps/drivers and dimmers by varying the voltage magnitude and frequency of the AFIC signal as well as the position (i.e., voltage output) of the dimmer. Visual observations were also carried out to investigate the correlation between measured flicker indices and visually observed flicker. This paper presents the test results that have been analyzed in terms of types of technologies used in LED lamp/driver and the variables in the AFIC signal.