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Nowadays one of the main problems Electrical Companies have are failures due to transportation network incidents, not only for the supply interruption time but also for the energy that must be absorbed by the network. Specially problematic are subterranean cables on cities and aerial lines in forest and rough mountain places where measurements are difficult to be done. High voltage lines’ and substations failures can be caused by many reasons but main causes GCM can cope with are:
- An excess of current increasing the temperature.
- An excess of Voltage can cause isolators damage and deterioration in Lines and Substations.
The increase in voltage is very difficult to detect because it produces a weak decreases in current some times imperceptibles. The temperature measurement by using fiber optic sensors, by using Raman effect, is one of the most used methods of failure detection and prediction because every change in cable parameters represents a temperature change in the failure point. In spite of this sensors provide of a spatial resolution between 1 and 3 meters, the reach is limited to distances below 10Km and, moreover, it has the inconvenience of its difficult installation in already operating lines. On the other hand, temperature reach by the line in a point not only depends on the current circulating through it but also on other external factors like the thermal terrain resistivity, cabling gathering and grouping, resonance effects, power transportation variations, etc. Al possible effects influence in the cable characteristics and, therefore, on its primary electrical parameters: kilometric resistance, conductance, capacitance and inductance, allowing to affirm that known each of its parameters it is possible to know the state of the cable or line and forecast possible failures.
GCM Proposal
GCM’s proposal is based on its own technology to characterize the transfer function of any cable with an extreme precision. The precision can be controlled dynamically, allowing the detection of changes that should be imperceptible using other techniques. Likewise, measurement is done without neither interrupting the service nor disconnecting any network’s equipment.
Measurement is done by transmitting a low power encoded signal in a network (or line) point called insertion point. In the measurement point a similar equipment is used to analyze the signal received from the transmitter through the line corresponding to the response of the cable and identifying its parameters. It is also possible to analyze its frequency response and time response in order to obtain a better information of it.
On the other hand, due to the special features of the technology, it is possible to determine where the changes are producing in the network as it can be used as a reflectometer.
This technology has been proven over ADSL and high voltage subterranean cables. More than ten years of research and experience in analyzing wave propagation initiated into the Electronic Department of Alcalá University (Madrid), has drive GCM to develop its identification techniques allowing increasing the resolution, sensitivity and precision necessary even in very noisy environments.
Fundamentals
The fundamentals of the characterization is the transmission of a encoded signal by means of a transmitter equipment in a network point or node. The signal used occupies a selectable frequency band and it does not interfere with the rest of equipments connected to the network due to its low power white noise like properties. Every receiver process the received signal obtaining directly the transfer function of the cable and identifying Its primary parameters from it. Likewise, due to the temporal properties and noise immunity the system Can detect, in real time, the spatial point of failure as well as the unauthorized connection and Disconnection of loads in network due to the reflection signal suffer in the connection point detected as a return signal in the transmitter. The time of characterization is smaller than a second with high precision, even with signal to noise ratio below -30dB (1000 times higher noise than signal). Likewise, in case of need or when system condition requires, it is possible to increase its sensitivity and immunity to noise to SNR below -60dB (1000000 times higher noise than signal) within a delay below 10 seconds between measurements.
For more information about licensing and partnership, please send us an e-mail at license@gcmcom.com