Page 195 - AJWEP-22-6

Municipal street lighting retrofit in Bulgaria

Figure 11. Photographs illustrating the technical solution involving the extension of existing park poles and
the installation of street-type light-emitting diode luminaires

segment. By updating the luminaire specifications unauthorized access to the lighting cabinet.
and their respective power ratings in the graphical (iv) Information on non-functioning street luminaires,
model developed during the energy audit, the accurate indicating the affected circuit branch and the
quantitative and energy performance parameters of the number of defective units.
modernized lighting system were established. (v) Backup battery for autonomous emergency
A summary of the luminaire types, rated power, operation during prolonged power outages.
and quantities implemented in the modernized street (vi) Archived data on the operational status of the street
lighting systems is provided in Table 6. lighting system.
The system should also support the integration of
2.3. Implementation of a modern street lighting additional functionalities, if needed, either through
management and control system updates to the existing software modules, the addition of
Modern street lighting control systems use wireless 30 new ones, or by integrating new technical components.
communication technologies based on global system for This would enable effective energy management for
mobile communications (GSM)/general packet radio the street lighting system and facilitate planning and
service (GPRS), Internet of Things, and other smart optimization of maintenance operations.
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systems for digital and cloud-based management. 32-34 The project proposes dimming of the power and
The control system was modernized by replacing the luminous flux of the LED luminaires, allowing for
old power supply boxes (Figure 12) with new control and energy reduction through pre-programmed or remotely
monitoring cabinets (CMCs) (Figure 13). These cabinets controlled LED drivers. This applies to streets of higher
are equipped with the necessary protective, switching, lighting classes, where luminaires can be dimmed to
and metering devices, as well as a GSM/GPRS controller- a certain percentage of their nominal power during
modem for communication with a centralized monitoring nighttime periods with reduced traffic intensity. During
and control station running dedicated application software. these hours, the lighting class of the street is considered
Communication between the CMCs and the to temporarily shift to a lower class with less stringent
centralized monitoring and control center is facilitated requirements.
through the GSM network of a mobile operator, as In the present project, dimming was implemented
illustrated in Figure 14. via pre-programmed drivers, reducing the luminaires’
The new street lighting control system must provide, power output on streets of lighting classes M4 and M5
at a minimum, the following functionalities: to 60% of their nominal power during the time period
(i) Remote switching of street lighting on and off from from 11 p.m. to 5 a.m.
a central control (dispatcher) center. The interface of the cloud-based control and
(ii) Real-time (online) information on electricity monitoring software for the street lighting system
consumption. in Pavlikeni is presented in Figure 15, and the power
(iii) Alarm notifications in case of unauthorized dimming process visualization module is shown in
connection to the street lighting network or Figure 16.

Volume 22 Issue 6 (2025) 189 doi: 10.36922/AJWEP025310242