Connect Legacy Infrastructure on Modern Networks

| 3/20/2014 11:49:33 AM

Thermal energy distribution systems are an example of systems that need a way to deploy remote supervisory control and data acquisition (SCADA) throughout what can be massive networks. Here’s how one utility company has used modern networking to improve efficiencies and reduce maintenance response times.

Legacy District Heating System

A legacy district heating system developed
a way to deploy modern networking.

Most network operators have some legacy infrastructure that was never designed or built to support remote monitoring and control.

As an example, let’s look at some thermal energy distribution systems. The steam tunnels at the University of Illinois date back to the early 1890s. The French village of Chaudes-Aigues Cantal has a district heating system that dates all the way back to the 14th century. You’ll find thermal energy distribution systems all over the world. While they’re quite cost effective if the system is large enough, they do tend to predate modern data networking.

Pražská Teplárenská a.s is a utility that operates a district heating system in Prague. The network has 265,000 customer connections, 49 heating plants and laid out end to end it would be 696 km long.

Wireless Connectivity

Pražská Teplárenská a.s needed a way to deploy remote supervisory control and data acquisition (SCADA) throughout the system.  Remote monitoring and control of boiler rooms and heat exchange stations would let operators improve their efficiency and reduce response times when disruptions occurred. Frequency controllers on circulation and boiler feed pumps would cut electrical costs. Remote temperature gauges could track heat loss and insulation status, and remote meter reading would improve invoice accuracy while cutting labor costs.

The Pražská Teplárenská a.s system already combined some new, cutting edge technologies with legacy infrastructure. Their Malešice CHP plant, for example, was equipped with new prompt-gamma neutron activation coal analyzers that enable real-time analysis of the hard coal being supplied to a boiler. Real-time coal quality data lets operators apply appropriate process control measures like sorting, blending, and coal homogenization. Operators can increase energy efficiency while simultaneously reducing pollutants and emissions. Gamma neutron activation coal analyzers didn’t exist when the system was originally designed and built. Data networking connections didn’t exist back then, either, and creating them would be problematical in a city more than 1000 years old with winding streets and canals. There were many places where installing cable connections, whether copper or fiber, would have been impractical. Pražská Teplárenská a.s needed a wireless solution.

Compatibility issues

The company chose cellular routers from B&B Electronics’ Czech Republic-based subsidiary, Conel. Cellular routers make it possible to install SCADA systems anywhere there’s cell phone service by connecting equipment to the Internet via the cellular network.  

The routers communicate with the central control using standard TCP/IP, but they’ll connect to remote networks and devices using a variety of protocols.  The Prague heating system put that capability to good use. Heat meters on Modbus loops connected directly to the cellular routers via the routers’ built-in Modbus hardware interfaces, and the routers provided the Internet connection.  The same cellular routers can also connect equipment via Wi-Fi, Ethernet and RS232/422/485.  

Role of Cellular Routers

Security is an important element in any wireless application.  Pražská Teplárenská a.s chose routers that supported a wide variety of security technologies, including firewalls, IPsec, DES, 3DES, AE modem S128, AES192, AES256, MD5, SHA1, DH2, DH5, pre-shared key, X.509, OpenVPN, LZO, NAT Rules, Redirect Gateway, pre-shared secret, username/password, X.509, L2TP, and GRE. By setting up Virtual Private Networks (VPNs) the company is able to use the cellular system as securely as if it were proprietary infrastructure.

Remote monitoring is done via an application based on the Simple Network Management Protocol (SNMP). The central control receives real time information about each node on the network, as well as information about the routers themselves. (System engineers can monitor a wide range of router parameters, like operation state and signal strength.)  The routers are based on the Linux OS, which lets users modify firmware and create custom modifications for specific applications. The routers can automatically upgrade their configuration files and firmware from the company’s central server. This allows for simultaneous, mass reconfiguration of every router on the network.

Another option in data networking is to use the Ethernet port in a cellular router to connect additional equipment like IP cameras.  By collecting many different kinds of data from numerous devices, cellular routers can allow for remote monitoring and control virtually anywhere. They not only bring new capabilities and efficiencies to legacy installations, they give operators the freedom to use multiple data networking protocols in new installations as well.

The low latency and massive bandwidth of the new 4G LTE networks will make cellular data networking even more impressive.  We will soon begin to see innovative new M2M applications that can make full use of 4G LTE’s capabilities. But those old district heating systems will still be chugging away too. While many of their components may not be as cutting edge as 4G LTE, it will always be hard to beat the comforting sound of steam hissing in your radiator on a cold winter morning.


298 Comments Click here to read/write comments
Subscribe to Bill's Wireless Blog