Real Time Thermal Rating (RTTR)
In order to operate power grids, such as transmission lines and distribution networks, with maximum efficiency and at higher voltages, advanced technology is needed to maximize power load and simultaneously retain high safety standards. One of these advanced technologies is RTTR.
Real Time Thermal Rating (RTTR) or Dynamic Cable Rating (DCR) continuously calculates the conductor temperature of a power grid by taking current load, load history, thermal conditions and other factors into account. At the same time it predicts the maximum permissible load for steady state and emergency situations. Based on industry standards IEC 60287, IEC 60853 and finite element modeling, you can operate your network at the highest possible safe ampacity levels with excellent predictive capabilities.
The RTTR calculation is based on precise thermal models reflecting the soil/ambient conditions along the high voltage power cable. The RTTR module calculates pertinent information such as conductor temperature profiles and emergency ratings in real-time using fast Kalman Filter technology.
RTTR seamlessly integrates into AP Sensing’s SmartVision software package, enabling the identification of critical locations and triggering (pre-)alarms when respective thresholds are reached. RTTR is the ideal tool for comprehensive asset monitoring of HVAC & HVDC underground and submarine cables.
RTTR functionality comprises of:
- The calculation of conductor temperature profiles along power cables from Distributed Temperature Sensing (DTS) and load data
- The calculation of steady-state ampacity, i.e. maximum permissible load
- Emergency ratings, i.e. real-time prediction of maximum conductor temperature, emergency time or emergency current for up to one week
AP Sensing has a proven history providing power cable monitoring solutions including RTTR and has worked together with industry leaders to achieve precise, reliable and validated data. Rating results are fully integrated into AP Sensing’s SmartVision software platform and are easily interfaced into the operator’s load dispatch center via standard protocols such as Modbus TCP, IEC 61850 and IEC 60870-104.
AP Sensing’s RTTR module is a state-of-the-art software module and enables the optimal use of temperature information from monitored power transmission and distribution networks. Thermal rating of AC and DC circuits is supported, enabling the optimized monitoring of all modern onshore and offshore underground power cables (single-core and three-core cables). A wide range of installation configurations for single and multiple circuits is supported including a wide range of sensor positions.
Steady State and Emergency Ratings
Using continuous temperature measurements of the cable surface (fiber position) and the available load data, RTTR calculates the temperature of the conductor core.
The RTTR engine can predict:
- The temperature of the cable in the future (up to 1 week),
- The time it will take the cable to reach the specified limit,
- The maximum current that the circuit can carry to reach the specified temperature.
RTTR Modeling Capabilities
Virtually all types of cable designs can be modeled in AP Sensing’s RTTR such as: single-core, three-core, sheathed cables, subsea composite cables, and concentric neutrals.
Numerous cable-laying conditions can be modeled, such as directly buried, duct banks, thermal backfills, buried ducts and pipes, submerged cables, and many more. The cable phases can be touching or non-touching, single or multiple circuits installation combined. AP Sensing’s RTTR solution can model several
materials with individual thermal parameters, for example stratified soil layers, multiple duct banks and thermal backfills. The model range is continually being extended.
Various types of fiber positions verified by Finite-Elements-Method (FEM) simulations can be covered:
- Internal sensor, e.g. in cable sheath (position specified by cable layer),
- External sensor cable, attached to power cable or pipe,
- Remote sensor (distant to power cable or pipe),
- Special positions for trefoil touching circuits.
Benefits of RTTR:
- Prediction of time before maximum temperature is reached.
- Identification of dynamic or permanent load pattern and the maximum conductor temperature limit for the cable.
- Temperature of the cable at the end of a given period of (over) load for improved safety.
- The maximum permissible load of the cable for an emergency situation.
- Lower maintenance and operating costs.
AP SENSING SUCCESS STORIES
We have hundreds of satisfied customers worldwide!
220 KV Power Circuit with Temperature Map Updated Case
A new 220KV underground power circuit traverses many different types of soil conditions along its 25 km length. AP Sensing’s fiber optic based DTS (Distributed Temperature Sensing) solution was selected by the network operator RTE (Réseaux de transport d'éléctricité), based on its reliability and ruggedness, as well as the innovative asset visualization capabilities.
Taiwan Mass Rapid Transit Updated Case
AP Sensing was selected to monitor the power cable in a new metro tunnel. This is the first power cable temperature monitoring system to be used in the Taipei MRT. The Linear Power Series solution continually monitors the temperature of high-voltage power cables. The DTS (Distributed Temperature Sensing) solution ensures a stable, safe and efficient power transmission and distribution.
115kV Underground Power Cable Saudi Arabia June 2020
Khudriyah-2 BSP is a new grid station situated on the outskirts of Dammam city, Kingdom of Saudi Arabia. Our Distributed Temperature Sensing (DTS) system was deployed to monitor the temperatures of two 115 kV underground circuits, providing thermal profiling and insights into the the actual conductor temperature and transient statuses with Real Time Thermal Rating (RTTR).
Underground Transmission Cable Monitoring Pakistan May 2020
AP Sensing is monitoring a 132 kV underground transmission cable for Karachi Electric. This cable experiences greater loads than nominal lines, as it feeds energy to a steel mill with high energy throughputs and frequent consumption cycles. Our solution provides end-to-end temperature monitoring to reduce thermal overload and cable faults. Additionally, RTTR and our asset viewer software enhance operational insight.
Underground Power Cable Utilizing DAS March 2020
An AP Sensing Distributed Acoustic Sensing (DAS) system is monitoring a 6 km high-voltage power cable in Germany. A key feature of DAS is the ability to immediately detect and locate cable faults. This helps optimize transmission and distribution networks, and reduces costly and unnecessary operational costs and asset downtime.
Kriegers Flak Offshore Wind November 2019
Denmark's largest offshore wind farm required a reliable, high-performance solution for protecting and monitoring cable loads and immediately detecting faults. 6 DTS units and 9 DAS units are in use for monitoring 300 km of this asset; AP Sensing's SmartVision visualization software is utilized for a real-time graphic overview of all temperature and acoustic data.
Underground Power Monitoring Skanste Riga Aug 2018
An AP Sensing fiber-optic DTS (Distributed Temperature Sensing) solution was selected to monitor power cables on two underground circuits in Latvia. This successful installation involved one DTS N4425A device with six channels, as well as SmartVision and RTTR (real time thermal rating).
Press Release Fiber Optic Sensing Association NOV 2017
The Fiber Optic Sensing Association (FOSA) today released details on more than 1,300 installations of distributed fiber optic sensing (DFOS) around the world, the largest representative sample ever published. AP Sensing is proud of our global contributions for pipeline leak detection, high voltage power cable monitoring and fire detection.
Offshore Windpark DTS and DAS Monitoring SEPT 2017
The operators of an offshore wind farm located off the west coast of Denmark wanted a monitoring solution to locate cable faults immediately after they occur. They chose AP Sensing for our unique combination of DTS (Distributed Temperature Sensing) and DAS (Distributed Acoustic Sensing) capabilities.
Subsea Power Cable Monitoring with SmartVision and RTTR FEB 2017
The oil platform operator Engie needed a monitoring solution for their medium voltage (35kV) subsea power cable, which provides the power for the platform operations. AP Sensing was selected not only because of our ruggedness, reliability and superior support services, but also for our SmartVision™ and RTTR capabilities.
Subsea Power Transmission Link Sicily Calabria July 2016
The extra high voltage power links run between power stations in Sicily and Calabria, crossing the Messina straits. To monitor and protect the overland sections of this important link, AP Sensing’s fiber-optic based DTS (Distributed Temperature Sensing) solution was selected.
Olympic Park Brazil June 2016
The Olympic Park is the main center of competition for the 2016 Summer Olympics in Rio de Janeiro. Covering over 1 million square meters and including 9 different sports facilities, a new power substation was constructed to handle the enormous power demand in the park. AP Sensing’s fiber-optic based DTS (Distributed Temperature Sensing) solution was selected to monitor this valuable infrastructure.
Wind Park Subsea Power Cable Monitoring Shanghai Oct 2010
The Donghai Bridge Wind Farm in Shanghai is the second largest bridge in the world. The wind farm is the first commercial offshore wind park, and was completed prior to the 2010 World Expo in Shanghai. AP Sensing was selected to monitor the subsea power cable with an approximate length of 15km.
Transmission and Distribution Network Jan 2013
A leading Australian network operator wanted to gain monitoring insight into his distribution network: to monitor the medium-voltage power cable’s condition, identify hotspots and bottlenecks, and to minimize risks and costs for maintenance and in emergency situations. The operator can now operate his network at the highest possible safe ampacity level.
Power Cable Tunnel Monitoring Shanghai Mar 2010
The World Exposition 2010 Shanghai China (Shanghai Expo) was held at the waterfront area on both sides of Huangpu River in Shanghai from May to October, 2010. AP Sensing provided its leading Distributed Temperature Sensing (DTS) system, the “Linear Power Series”, to monitor and secure the first 500kV power cables in Shanghai installed in a power cable tunnel over a distance of 20km.
Power Circuit Monitoring Czech Republic Jan 2010
In 2009 Brugg Cables installed a new 110 KV power circuit within the city limits of Prague. To protect valuable assets with Distributed Temperature Sensing (DTS) technology the end customer chose to equip the new circuit with a fiber optical sensor cable and permanently monitor the temperature profile with an AP Sensing Linear Heat Series instrument.
High Power Underground Cable Monitoring March 2010
Underground utilities are “the power” beneath large cities. They feed the cities with electric power, gas and water. Failures in this sensitive infrastructure are costly and therefore USI Power selected AP Sensing’s outdoor DTS instrument to permanently monitor the temperature along a 220kV power circuit connecting Manhattan and Queens.
380 KV Power Circuit Monitoring March 2011
In 2010 a new 380KV power circuit was put into operation as part of a nationwide power grid improvement. Near Florence the high voltage circuit has buried sections in close proximity to a very populated valley and a historic church. The primary route was completed in trenches filled with thermal sand. The project also included challenging road crossings that used horizontal drilling to complete the construction.