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"Protection systems"
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Characterization of the Electrical Environment
A communication system must have adequate electrical protection in order to meet the reliability standards for commercially acceptable service and to keep down maintenance expenses. This report characterizes, from the viewpoint of electrical protection and coordination, the conditions of the electrical environment to which communication facilities are exposed. It gives consideration to both present and anticipated future conditions, and covers such topics as the effects of lightning, interference from power networks, electric shock, earth potential gradients, corrosion, over-voltage in AC power utilization circuits,her and electromagnetic pulses.
Characterization of the Electrical Environment is a current reference on the design factors required to ensure reliable performance of communication facilities under field operating conditions. It will be useful as a manual for practicing engineers in telecommunications, and as a tutorial textbook in engineering schools in North America, Europe, and elsewhere.
eBook
Experimental Heat Loads for Electrothermal Anti-Icing and De-Icing on UAVs
Atmospheric in-flight icing on unmanned aerial vehicles (UAVs) is a significant hazard. UAVs that are not equipped with ice protection systems are usually limited to operations within visual line of sight or to weather conditions without icing risk. As many military and commercial UAV missions require flights beyond visual line of sight and into adverse weather conditions, energy-efficient ice protection systems are required. In this experimental study, two electro-thermal ice protection systems for fixed-wing UAVs were tested. One system was operated in anti-icing and de-icing mode, and the other system was designed as a parting strip de-icing system. Experiments were conducted in an icing wind tunnel facility for varying icing conditions at low Reynolds numbers. A parametric study over the ice shedding time was used to identify the most energy-efficient operation mode. The results showed that longer intercycle durations led to higher efficiencies and that de-icing with a parting strip was superior compared to anti-icing and de-icing without a parting strip. These findings are relevant for the development of energy-efficient systems in the future.
Journal Article
Cyber threat intelligence as team work : how to do team-work activities contribute to the success of cyber-crime initiatives, what are the central principles of' effective team-working', and how necessary are physically integrated teams in a time of inter-agency, online collaborative working ?
Criminology with cybercrime.
Book
Superhydrophobic Coating Solutions for Deicing Control in Aircraft
The risk of accidents caused by ice adhesion on critical aircraft surfaces is a significant concern. To combat this, active ice protection systems (AIPS) are installed on aircraft, which, while effective, also increase fuel consumption and add complexity to the aircraft systems. Replacing AIPS with Passive Ice Protection Systems (PIPS) or reducing the energy consumption of AIPS could significantly decrease aircraft fuel consumption. Superhydrophobic (SH) coatings have been developed to reduce water adherence to surfaces and have the potential to reduce ice adhesion, commonly referred to as icephobic coatings. The question remains whether such coatings could reduce the cost associated with AIPS and provide durability and performance through suitable tests. In this paper, we then review current knowledge of superhydrophobic and icephobic coatings as potential passive solutions to be utilized alternatively in combination with active systems. We can identify physical parameters, coating composition, structure, roughness, and morphology, durability as properties not to be neglected in the design and development of reliable protection systems in aircraft maintenance.
Journal Article
Application of synchronised phasor measurements to wide-area fault diagnosis and location
This study introduces a novel approach to power system fault diagnosis by synchronised phasor measurements. Conventionally, faults are diagnosed through the status of protective relays and circuit breakers which are activated following a fault. However, the hidden failures of the protection system has itself often been among the main suspects of partial or widespread blackouts. This study proposes an alternative fault diagnosis approach independent of the function of the protection system. An analytical method is introduced for power system fault diagnosis using dispersed synchronised measurements and bus impedance matrix (Zbus). Fault inception is first detected by local phasor measurement units (PMUs). Fault diagnosis is then carried out in a hierarchical manner so that first the faulted zone of the system is diagnosed, next the faulted line in the faulted zone is diagnosed and finally the fault point along the diagnosed line is located by gradient descent. The proposed method is applied to the WSCC 9-bus, where fault incidents on all of the transmission lines are examined. Moreover, the proposed method is successfully applied to the IEEE 118-bus test system consisting of 28 PMUs, which demonstrates successful fault diagnosis and location for a large-scale power system despite the limited coverage of PMUs.
Journal Article
Protective relaying : principles and applications
\"Maintaining the features that sent the previous edition into 10 printings, Protective Relaying, Second Edition covers large and small utility systems as well as industrial and commercial systems ... provides a completely new treatment of generator protection in compliance with the most recent governmental rules and regulations ... supplies expanded information on symmetrical components ... delineates individual protection practices for all equipment components ... furnishes an overview of power system grounding, including system ferroresonance and safety grounding basics ... analyzes power system performance during abnormal conditions ... describes the relationship of input source performance to protection ... and more.\"--Jacket.
Book
Fault Tracing Method for Relay Protection System–Circuit Breaker Based on Improved Random Forest
The incorrect operation of protective relays and circuit breakers will significantly compromise the safety and stability of power systems. To promptly detect the faults of the relay protection system and the circuit breakers in time and to ensure the operational reliability of these protective devices, this paper proposes a fault tracing method for a relay protection system–circuit breaker based on improved Random Forest. Firstly, an analysis is conducted to identify the causes of incorrect operation of the protective relay and the circuit breaker. The fault types and corresponding alarm messages for the relay protection system and the circuit breaker are categorized, and the alarm feature set is constructed. Then, the Random Forest is improved and trained to develop the fault tracking model. Finally, the operation evaluation process is developed to determine the incorrect operations of the protective relay and the circuit breaker, and the fault tracking model and fault tracking process are then employed to locate the faults of the relay protection system and the circuit breaker. The experimental results demonstrate the method’s capability to accurately track faults in the relay protection system and the circuit breaker, thereby assisting operation and maintenance personnel in troubleshooting and highlighting its promising practical potential.
Journal Article