Time-Aware Monitoring of Overhead Transmission Line Sag and Temperature with LoRa Communication

Abstract

The techniques of Dynamic Line Rating (DLR) for Overhead Transmission Line (OTL)’s are currently dynamically developed. DLR systems typically rely on weather, temperature, inclination, and current measurements to calculate tension and sag, where sensors need to be installed directly on wires. Such systems are very reliable and ensure high accuracy in determining maximum allowable current. However, their installation may require switching off the transmission line from the operation. In order to receive precise values regarding the actual operating conditions of the whole transmission line, DLR sensors measuring wire temperature or tension should be installed at many points of OTL. The minimum number of installation points should cover at least each tension section and critical spans, thereby increasing installation costs. The alternative method that allows for the monitoring of OTL is the use of the vision system based on cameras. Installed on the OTLs’ poles, cameras can take photos which, appropriately processed, can provide data about the sag and temperature of wires, without the necessity of switching OTL from the operation for installation or further maintenance. Such a vision system facilitates also data transmission, because it does not require measurement data to be transmitted from the sensor station installed on the wire to the base station located on the pole (for instance, via radio). This article aims to present the concept of a vision system that monitors sag and temperature of Overhead Transmission Lines (OTLs)’ using Long Range (LoRa) wireless communication and data transmission. The developed system consists of a camera and a microcomputer equipped with LoRa communication module. The whole system monitors OTLs’ spans by taking photos, processing images for wire sag-temperature estimation, and sending results to the operator’s Supervisory Control And Data Acquisition (SCADA). The system communication architecture is also proposed and investigated for data transmission time when monitoring the whole OTL.

Minimum Frequency and Voltage Stability Constrained Unit Commitment for AC/DC Transmission Systems

“…Equation (3) represents the DC voltage-current relationship which depends on the DC transmission system configuration (i.e., V dR , V dI , and I d ). After getting the active power of both rectifier and inverter by Equations (4) and (5), the exchange reactive power between AC and DC system could be calculated through Equations (6) and (7) by considering reactive compensation capacity Q CI and Q CR .…”

“…In recent years, some effort has been spent by power engineers and researchers to investigate the optimum operation scheme of the alternating current /direct current (AC/DC) hybrid power system, such as researching the transmission power limits with temperature [4][5][6]. The simplest approach is to treat HVDC transmissions as constant power injections or withdrawals.…”

IoToF: A Long-Reach Fully Passive Low-Rate Upstream PHY for IoT over Fiber

“…For local and personal area networks, the Wi-Fi, Bluetooth low energy (BLE), Zigbee and thread standards [14], Z-wave protocol [15], radio-frequency identification (RFID) [16,17], and near field communication (NFC) [18] can be highlighted. For wide areas, the long-term evolution (LTE) [19], Neul's ultra narrow-band (UNB), Sigfox and LoRa are broadly used [14,20].…”

Monitoring of the Efficiency and Conditions of Induction Motor Operations by Smart Meter Prototype Based on a LoRa Wireless Network

“…There are some applications for LoRa such as in [37], which studies the concept of a vision system that monitors sag and temperature of overhead transmission lines using LoRa wireless communication and data transmission, the developed system consists of a camera and a microcomputer equipped with LoRa communication module. Also, [38] presented the development of relays that communicate with each other using LoRa, which allows for the combination of the cost-effectiveness and ease of wireless networks installation with long range coverage and reliability.…”