Telecom sites such as repeater towers, fiber huts, microwave towers, and power substations rely heavily on uninterrupted power supply for their operations. As these are often situated in remote areas, it's essential to have backup power generators that can kick in during power outages. To ensure these backup generators are always ready to operate, regular monitoring is crucial.

This guide will explore how to monitor backup power generators, commonly powered by propane/LPG or diesel. We'll discuss both traditional sensors that output 0-5 VDC or 4-20 mA and modern protocols like MODBUS via RS-485.

NOTE: While some devices report to the cloud and use apps for monitoring, we'll focus more on methods suitable for security-focused organizations preferring on-premises equipment and closed networks.

Step 1: Understand the Basics

Before we dive into the monitoring process, let's familiarize ourselves with some basic terms:

• 0-5 VDC or 4-20 mA sensors: These are traditional analog sensors that measure variables like temperature, pressure, or fuel level and convert them into voltage (0-5 VDC) or current (4-20 mA) signals. This can be measured by the general-purpose analog inputs on your RTU.
• MODBUS protocol: This is a communication protocol commonly used for transmitting information over serial lines between electronic devices. It's a method often used to connect a supervisory computer with a remote terminal unit (RTU) in the supervisory control and data acquisition (SCADA) system. MODBUS usually puts a tremendous amount of data at your fingertips, albeit with the new challenge of needing to interpret complex register maps and configure settings in your RTU or other monitoring device.
• RS-485: This is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. It is relevant for generator monitoring because it is the most common way that MODBUS messages leave the generator. Be sure you've ordered the appropriate hardware/software module from your generator manufacturer. MODBUS is often optional, in many cases because the manufacturer would really prefer that you pay a monthly fee for cloud-based/app-based monitoring service.

Step 2: Set Up Monitoring Sensors

Fuel Level Sensors

Install fuel level sensors in the fuel tanks of the generators to monitor the fuel level continuously. These sensors can be analog type, providing an output of 0-5 VDC or 4-20 mA corresponding to the fuel level. Make sure the sensors are properly calibrated according to the size and shape of the fuel tank.

Generator Operation Sensors

These sensors monitor the generator's operation status. They can detect if the generator is running, idle, or in fault condition. The sensors can be connected to the generator's control panel and will provide an output signal indicating the generator's status. I've even go so far as to strap a D-Wire (DPS in-house sensor brand) vibration sensor

Temperature and Pressure Sensors

Temperature and pressure sensors are crucial to monitor the operating condition of the generator. Overheating or pressure buildup can cause severe damage to the generator. These sensors are usually installed on the generator's engine and cooling system.

Battery Voltage Sensors

These sensors are installed on the generator's starting battery. They monitor the battery voltage to ensure that the battery is in good condition and ready to start the generator when required.

Step 3: Establish Data Collection

After setting up the sensors, the next step is to collect the data they provide. Here, the use of a SCADA system or a similar data acquisition system can be beneficial. The data acquisition system will collect the output signals from the sensors and convert them into meaningful data.

To securely connect the sensors to the SCADA system or data logger, you can use the RS-485 communication standard with MODBUS protocol. It allows reliable and secure data transmission over long distances, suitable for remote locations.

You'll then most likely want to route data back across your network to some kind of central collection server. It's possible to manage your data logger directly via web interface, but the total storage space can be limiting. When you get beyond 10 remote sites, it's also unwieldy to connect to 10 different web interfaces individually.

A protocol like SNMP is commonly used in this layer of your data collection hierarchy. This is a network management protocol that allows you to collect configuration information, like the IP address of your data acquisition device. You can then use this information in combination with SNMP traps to send alerts when certain conditions are met.

Step 4: Data Interpretation and Monitoring

Interpreting data in real-time is crucial for effective generator monitoring. A good monitoring system should have the capability to interpret the data and provide meaningful insights. For example:

• Fuel level: If the fuel level drops below a certain point, the system should alert the operator to refill the tank. Analog sensors give you the flexibility to set any percentage level(s) you want as the threshold(s), but even a discrete "low fuel! 25% remaining!" sensor with a fixed threshold is a huge help, especially during a hurricane or other widespread crisis.
• Generator status: The system should be able to interpret if the generator is running, idle, or in a fault condition, and alert the operator accordingly. These statuses classically arrive to your monitoring system via one or more contact closures, but you're increasingly seeing digital protocols like MODBUS taking over this role and offering 1000+ different data points to monitor.
• Temperature and pressure: If these parameters exceed their normal range, the system should trigger an alarm indicating possible generator failure. Ideally, your monitoring system will let you choose the ranges that trigger alerts.
• Battery voltage: If the battery voltage drops below the normal range, the system should alert the operator about potential starting problems. In this case, we're talking about

Step 5: Routine Maintenance and Checks

Routine maintenance checks should also be incorporated into the monitoring plan. Regular servicing, including oil and filter changes, are essential for the generator's longevity and reliability. Sensors can give you clues here, but a generator is still an engine that needs recurring human visits at some minimum frequency. Any irregularities noticed during monitoring should be promptly addressed to prevent any unexpected shutdowns or failures.

Step 6: Emergency Procedures

Establish emergency procedures if abnormal operating conditions are detected. This may involve shutting down the generator, dispatching maintenance teams, or switching to a secondary backup power source.

Step 7: Contact DPS for Assistance Getting Started

Monitoring backup power generators at remote telecom sites is an essential task to ensure uninterrupted operations. Using traditional or modern sensor technologies in combination with a secure, reliable communication protocol such as MODBUS over RS-485, organizations can maintain effective, real-time monitoring of their generator systems, ensuring they are ready to step in when power outages occur.

DPS is always standing by to have a conversation with you. We do this kind of thing all the time, so we're ready to help. We've helped our clients prepare for hurricanes, floods, wildfires, and miscellaneous power failures.

Contact us for assistance finding the right solution and getting started with your backup power generator monitoring system. We'll make sure you stay up and running - no matter what the world throws at your remote facilities.

Call DPS at 1-800-693-0351 or email sales@dpstele.com