Increased reliability through continuous and remote substation asset monitoring

14.10.2016

Conditioned-based maintenance (CBM) is essential for electric utilities and most utilities have initiatives and investments to realize these goals. The use of thermography is a well-proven technique for monitoring conditions and detecting faults in electrical equipment. 

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Figure 1 TS724DV-PT System in Operation

For many years, portable thermal imaging cameras were known as a reliable tool in the condition-based and preventative maintenance of electrical distribution systems in low-, medium-, and high-voltage installations, where they are often used at periodic time intervals. 

However, manual thermography inspections limit the practicality and scalability of applying CBM. There is a significant cost related to the inspections and the data gathered tends to be imprecise. Finally, even if good data is collected, there is a shortage of effective tools and resources required to analyze the data. Advancements in thermography allow this proven CBM tool to be automated thus enabling utilities to better realize CBM.

Detecting Equipment Problems before Failure

With a great deal of equipment at electrical power substations nearing the end of its useful life, the potential for faults or the complete failure of these devices due to their age increases. The use of thermal imaging in the detection of equipment problems is attractive because the non-contact nature of the technique allows assessments to be done safely while equipment is kept in operation. 

However, manual and periodic inspections have their limitations. First of all, they are expensive since workers need to travel and haul equipment, which takes them away from other important work. Manual inspections are also prone to error and the results are highly variable depending on load and weather conditions. In addition, due to limited resources, the biggest difficulty may be finding time or the right people to interpret the results of the manual inspections. 

Optimized maintenance concepts in this industry call for automated methods that are data driven. New advancements in data anomaly analysis and continuous monitoring of critical substation connections and assets, such as transformers, bushings, disconnects, and capacitor banks, provide an automated early-warning detection of developing failures. Electric utilities need an automated, data-driven method to analyze electrical equipment.

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Figure 2 System Network

Replacing manual inspections that may be erroneous or periodic with a more rigorous and continuous automated monitoring method allows operators to identify transient thermal events that were not detectable with manual inspections. By deploying thermal imaging systems at critical locations throughout the electrical power distribution system, electric utilities have access to continuous, online monitoring without the personnel constraints and limited resources. The end result is the decrease in maintenance activity and the procurement of replacement devices becomes a viable strategy. Furthermore, the safety and reliability of the substation equipment is increased and the loss of the distribution of electrical power from a major asset failure can be prevented.

Automated & Remote Thermal Imaging Monitoring

Designed with advanced maintenance-free electronics, the ThermalSpection™ 724 system offers a high degree of accuracy for demanding electric power utilities while accurately measuring asset temperature without contact in even the most adverse environments. This system allows utilities to continuously monitor the temperature profile and long-term thermal trends of assets within an electrical power substation remotely. This allows for incredible condition-based maintenance by allowing operators to automatically detect temperature deviations from normal operating conditions in real-time. 

The ThermalSpection™ 724 Dual Vision – Pan Tilt (TS724 DV-PT) system includes both thermal and visual imagers in a hardened enclosure on a positioner with a continuous 360° pan range and tilt range of ±45°. The enclosure protects the cameras from weather and temperature changes and uses a solid state cooling system for reliable, long-term installation. The solution can combine multiple devices, including optional fixed thermal imagers and fixed single point infrared pyrometers, for the most comprehensive system solution for monitoring electric power substations.

Data Automation and Informing Users

Each TS724DV-PT system also includes a stainless steel junction box with all of the necessary hardware for power and data transfer, including a hardened umbilical cable to easily connect the camera to the junction box. The umbilical cable serves as the communication link from the camera to the controller and allows for quick access to the camera’s thermal readings and configuration options.

The local controller can be a utility-approved computer or a server from LumaSense, which will run the included LumaSpec RT software. This software allows the user to define automated “inspection tours” of the substation or industrial setting to monitor multiple areas. Operators can also use the software pan and tilt controls for manual positioning. Data from the controller is also published to existing data historians, for example PI from OSIsoft, using Modbus or OPC protocols.

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Figure 4 Substation Thermal Image

In parallel, data can optionally be published to a Microsoft SQL database using LumaTrend server. This provides a central repository for data and images from substation and plants throughout a user’s enterprise. With such a system, centralized engineering and operations staff can easily review data and images from all cameras from anywhere on the corporate network. The data collected by the cameras can be put in the hands of experts, wherever they may be. The thermal images and temperature data can also be setup to trigger alarms, automatically publish reports, and perform retrospective analysis.

LumaTrend analyzes that data over time using built-in industry standard analytics to help provide early detection of problems and can use the images to create time-elapsed video (both infrared and visual) of the equipment monitored. Because of this technology, this software can help identify transient thermal events not detectable with manual inspections.

Since this software uses authenticated web browser access, users can capture, access, and analyze data on managed assets remotely. Users can set up email notifications for reports, alarms, and warnings. Real-time notifications can be sent to experts who then review the data, suggest additional investigative action, and schedule conditioned-based maintenance.

Realizing CBM Using Fully Automated Data Collection and Analysis

By replacing periodic, error-prone manual inspections with a more rigorous and continuous automated monitoring system, utilities can gain a more accurate picture of the actual condition of ageing assets and high voltage equipment in their substations and grid. The end result is a sustainable, effective conditioned-based maintenance program for utilities.

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Figure 5 System Communication / data exchange

While the Thermalspection 724 system is a very accurate and reliable solution especially for substations and electrical switchgear monitoring of bushings, isolators, breakers, capacitor banks, busbars, and transformers, it is also used in industrial settings such as detecting hot spots in fuel storage facilities or monitoring for degradation of refractory in high temperature furnaces and vessels.  

Text Lenny Shaver, Sr. Director, Product Management,
LumaSense technologies Inc., Santa Clara, CA.

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