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Road lighting is an important element of road infrastructure influencing on the road safety. It helps road users to identify potential hazards on the road and reduces the risk of a road accident. Improving the energy efficacy of road lighting installations requires using new technologies. Currently, high-pressure sodium (HPS) lamps are still most commonly used in road lighting. Many of the luminaires with HPS lamps are still in good technical condition and there is no economic justification for replacing them (except improving energy efficacy). One of the methods of improving their energy efficacy is to replace the electromagnetic control gear (ECG) with an electronic ballast (EB). This replacement may affect the colorimetric parameters of the HPS lamps. Two methods to the estimation change of colorimetric parameters after the replacement of ECG to EB were used. The first is CIE TN 001:2014 and the second is ANSI/IES TM-30-15. The article also presents the advantages and disadvantages of these methods in relation to the evaluation of changes in colorimetric parameters of HPS lamps after the replacement of the ECG with an EB. After the replacement of ECG to EB, the smallest reduction of Ra (colour rendering index) occurred for the 150 W lamp by 31.30% and the highest reduction for the 70 W lamp by 65.52%. Considering the changes of the fidelity indicator Rf and gamut indicator Rg, their changes are significantly smaller than for Ra. The smallest change of Rf value was observed for a 150 W lamp (6.00%) and the largest for a 70 W lamp by 25.00%. In case of Rg, similar changes were observed—for 150 W lamp by 9.26% and for 70 W lamp by 21.88%. The ANSI/IES TM-30-15 method is more suitable for evaluating colorimetric parameters after replacing ECG with EB. Using only Ra to evaluate changes of HPS lamps colorimetric parameters after replacing the ballast type can lead to incorrect conclusions concerning changes of colorimetric parameters. Based on the ANSI/IES TM-30-15 method, it has been proposed to introduce the Δf,g indicator which determines the change of colorimetric parameters based on fidelity and gamut colour indicator.

Assessment of Colorimetric Parameters for HPS Lamp with Electromagnetic Control Gear and Electronic Ballast