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Related Concept Videos

Line Protection with Impedance Relays01:27

Line Protection with Impedance Relays

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Coordinating time-delay overcurrent relays in complex radial systems and directional overcurrent relays in multi-source transmission loops can be challenging. Impedance relays address these issues by responding to the voltage-to-current ratio, specifically measuring the apparent impedance of a line. These relays become more sensitive during faults as current increases and voltage decreases, thereby reducing the apparent impedance.
Under normal conditions, low load currents keep the measured...
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Differential Relays01:20

Differential Relays

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Differential relays are used to protect generators, buses, and transformers by comparing electrical quantities at different points. When a fault occurs, the difference in current between the two points triggers the relay to operate, opening the circuit breaker. Under normal conditions, the current entering (i1) and leaving (i2) a generator are equal. When a fault occurs, however, these currents become unequal, and the difference current flows in the relay operating coil, causing the relay to...
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Radial System Protection01:23

Radial System Protection

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Radial systems employ time-delay overcurrent relays to reduce load interruptions. When a fault occurs, the nearest breaker opens first, while upstream breakers remain closed due to longer delay settings. This approach ensures minimal disruption to the rest of the system.
In a radial system with a fault downstream of the third breaker, ideally, only the third breaker will open, isolating the fault and interrupting the load connected beyond it. The second breaker has a longer delay setting,...
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Pilot and Numeric Relaying01:21

Pilot and Numeric Relaying

412
Pilot relaying is a type of differential protection used in power systems. It compares electrical quantities at the terminals of equipment via a communication channel instead of direct relay interconnection. This method is essential for transmission lines where the terminals are far apart, typically up to 80 km for lines with 69 to 115 kV ratings. Four types of communication channels are used for pilot relaying:
412
Overcurrent Relays01:26

Overcurrent Relays

401
Overcurrent relays, crucial for circuit protection, are connected to the secondary current of a current transformer. There are two primary types of overcurrent relays: instantaneous and time-delay.
Instantaneous overcurrent relays activate immediately when the input current exceeds a predetermined value, known as the pickup current, instantly energizing the circuit breaker trip coil. This rapid response is vital for addressing severe faults quickly.
Time-delay overcurrent relays, on the other...
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Directional Relays01:25

Directional Relays

485
Directional relays, essential for managing unidirectional fault currents, enhance the safety and efficiency of power systems. On power lines equipped with directional relays, faults downstream (to the right) of the current transformer typically cause the fault current to lag the bus voltage by approximately 90 degrees, known as the forward direction. In contrast, upstream (left-side) faults may result in the fault current leading the bus voltage by nearly 90 degrees, termed the reverse...
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Design and Analysis for Fall Detection System Simplification
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User Context Detection for Relay Attack Resistance in Passive Keyless Entry and Start System.

Jing Li1, Yabo Dong1, Shengkai Fang1

  • 1College of Computer Science and Technology, Zhejiang University, No. 38, Zhe-Da Road, Hangzhou 310027, China.

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|August 14, 2020
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Summary

This study introduces a secure smartphone-based Passive Keyless Entry and Start (PKES) system. By detecting user context like activity and door closing, it effectively prevents relay attacks on modern vehicles.

Keywords:
PKEScontext detectionrelay attackssmartphone

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Area of Science:

  • Computer Science
  • Electrical Engineering
  • Cybersecurity

Background:

  • Passive Keyless Entry and Start (PKES) systems are common in modern vehicles.
  • PKES systems are vulnerable to relay attacks, compromising vehicle security.
  • Existing systems lack robust mechanisms to verify user proximity and prevent unauthorized access.

Purpose of the Study:

  • To propose a novel, secure smartphone-type PKES system model.
  • To enhance PKES security by integrating user context detection.
  • To mitigate the risk of relay attacks in keyless entry systems.

Main Methods:

  • Utilizing smartphone embedded sensors (barometer, accelerometer) for context detection.
  • Implementing algorithms to detect human activity and car door closing events.
  • Developing a system model that uses detected context to verify car owner's position.

Main Results:

  • The proposed method accurately detects user activities and door closing events.
  • Performance evaluation demonstrated high accuracy and effectiveness in diverse environmental settings.
  • The system successfully prevented relay attacks in simulated scenarios.

Conclusions:

  • Smartphone-based context detection offers a viable solution for secure PKES.
  • The proposed system effectively enhances vehicle security against relay attacks.
  • This approach provides a robust and practical method for next-generation keyless entry systems.