Individual vs Segment Streetlight Controllers

Individual vs Segment Streetlight Controllers

At first, it was candles that lit up the streets. To control the street lighting, every night, a person walked every street and lit up every light.

Gas-lit lamps were the next technological breakthrough until, at the end of the 19-th century, electric lighting began its worldwide rollout and light bulbs replaced the burning streetlights. Of course, individual lighting up the lamps was replaced by an electric switch, powering ON/OFF the entire distribution network from one place.

Manual control turned into automated lighting control.

The desire for automation has long existed for lighting services, mostly using light sensors or time-based scheduling. The light turns on and off automatically throughout the city, from one central switch, but the system remains basically the same – there is no power in the lighting network during the day, which does not allow powering other applications. In addition, daily runs and citizen complaints are the only ways to detect malfunctions.

As the Internet evolved and became omnipresent, people began to imagine: what if not only people, but also objects could connect and communicate through the network? The Internet of Things concept was born, where any and all objects could communicate, either with themselves or with control systems, creating unparalleled control and convenience synergies. But how do you connect your bike or your trash bin to the Internet? It was not long until engineers solved this question: a plethora of low power (so a battery can last years) IoT communication technologies appeared almost overnight.

In this context, public lighting systems also gained extensive, never-before-available control possibilities. Today’s smart street lighting solutions include intelligent streetlight controllers that facilitate a more effective, less energy-consuming and more sustainable street lighting operation.

Individual lamp control? Or lighting segment control?

If the smart controller is installed with every lamp, then we have individual control. The system can collect information and control each lamp in the grid. However, if installed inside the feeder pillar, smart controllers enable segment-level lighting for a cluster of lamps. It’s more affordable and faster to deploy, but you lose some pretty important perks.

Both individual and segment controllers allow on/off control, either from a computer or a mobile phone, electrical grid feedback, and even completely autonomous lighting operation. However, individual lighting controllers provide more features and benefits. To name a few:

  • Lamp-level dimming, better controlling energy consumption
  • Real-time malfunction alert, with lamp detailed data (including localization)
  • The lighting grid is powered even during the day (power and communication for other smart city devices) etc.

Challenges for upgrading to an intelligent street lighting solution

So why not upgrade to individual lamp control? One reason is that local governments are facing, among others, monetary shortcomings. Although LED lamps together with smart control bring significant energy savings, budgets are not suited for the city-wide streetlamp renewing investment. The streetlight management projects can become expensive and exhausting multi-year investments. 

Even so, there are many upsides to investing in a modern street lighting infrastructure. With detailed data at hand, municipalities can not only save costs on energy and maintenance, but also ensure faster outage responses, and make more informed decisions regarding the development of the city’s public lighting and Smart City Platform.

  • Limited control options for older infrastructure retrofitting
  • Existing power supply issues (voltage fluctuations, same lighting segment powered from different sources)
  • Lack of inventory and lamp information
  • High hardware and implementation costs
  • Long deployment times
  • Lack of integration with other city systems
  • Vendor-locked solutions and lack of scalability

Is it a good idea to choose segment control for your smart street lighting project?

Is it a good idea to choose segment control for your smart street lighting project?

A segment represents a fraction of a public lighting network and can comprise a cluster of up to 200 streetlight lamps (nodes) controlled from the same feeder pillar. The power supply network is structured in such a way that the segment controller turns the power on/off for all the poles connected to the respective panel, sometimes correlated with a central switch, a light level sensor or a timer.

A street lighting controller placed in the feeder pillar (segment control) comes with immediate benefits:

  • Street lighting autonomous operation
  • Remote manual ON/OFF control for the entire segment. Some systems even promise limited dimming capabilities
  • Detailed electrical measurements for the segment (feeder pillar) power supply and consumption
  • Lower implementation costs: one controller manages up to 200 street lights
  • Fast deployment: with an average 150 lamps per feeder pillar, a smart lighting control solution in a city with 15.000 lamps can be fully operational in just a few days
  • Easier to connect: feeder pillars have access to various IP communication networks, including FO and landlines

But there are a few shortcomings:

  • Dimming is most often not available
  • You cannot detect individual lamp malfunctions
  • The lighting grid is powered off during the day (you cannot power other applications from the lighting grid, slowing smart city initiatives)

Could an Individual lamp controller be more suitable for your smart lighting project?

Could an Individual lamp controller be more suitable for your smart lighting project?

Individual lamp control is handled via luminaire controllers which have lamp-level functionality and intelligence, allowing individual ON/OFF and dimming control. Besides these functions, luminaire controllers carry out measurements and analysis of different electrical parameters at streetlight level: under/overpower monitoring, voltage monitoring, phase failure and consumption mismatches.

Furthermore, malfunctions are reported in real-time to the street lighting control software and maintenance teams, long before citizens even notice.

Benefits of individual street lighting control:

  • Street lighting autonomous operation based on predefined schedules and/or light level sensors

  • Detailed manual control: remote ON/OFF and dimming control for each lamp

  • Real time malfunction reporting significantly improves maintenance efficiency, deploying maintenance teams with exact location and situation data

  • Wide range of electrical parameters monitoring: V, W, A, VAR, Wh, VARh, PF – energy awareness throughout the grid encourages street lighting service optimization

  • The lighting grid is powered during the day, which encourages smart city deployments. Street lighting is omnipresent throughout the city, which makes it the immediate choice when you need to power sensors, \CCTV cameras, traffic control systems and actuators

So, is individual lighting control perfect? Well, that depends.

  • It’s obvious that individual control needs individual controllers to be installed, which requires significantly more time and money than feeder pillar control would

  • Individual controllers can be quite bulky, sometimes negatively affecting the architectural output of the controlled lamps

  • As IP communications are rarely available for each street lighting pole, most individual control solutions require either compatibility with an existing communication technology (2G/3G/NB-IoT, for example) or even need to build their own communication infrastructure (radio or PLC)

  • The process of choosing and implementing the right communication technology for your smart city can become pretty cumbersome, influenced by multiple factors (including system requirements,  local RF regulations and available telecom operators)

To simplify the deployment of individual controllers, regulators and integrators have developed multiple form factors and standardized plug-and-play mounting options:

  • Mounted on-lamp through plug-and-play installation, Zhaga is a compact connector, developed especially for today’s slim LED fixtures. Produced according to a global lighting-industry standard, Zhaga connectors can be deployed on existing lighting infrastructure and integrated with third-party solutions. Zhaga sockets are suitable for outdoor installations.

  • The NEMA socket is a standardised connector for street lighting controllers, derived from the American socket standard. Using the ANSI C136.41 standard, NEMA sockets can be easily mounted through plug-and-play installation on NEMA compatible lamps. Powering up is automatic and the luminaire is available immediately for feedback and control. NEMA sockets are sealed and suitable for outdoor deployments.

  • Designed to minimize occupied space, the embedded streetlight controller is the best way to keep the lamp’s architectural value intact. Mounted inside the pole, the controller can be wire-connected into most luminaire designs and can be embedded straight from the lamp production line, allowing any producer to offer ready smart street lighting fixtures.

  • Pole-mounted controllers are the most flexible form factor option available, as they do not require any special connections or certain streetlamp types. With its IP66 protection rating and compact dimensions, the controller can be installed directly inside or on the lighting pole, so it can be used to retrofit existing street lighting with minimal visual impact and virtually no civil works