Attack resilient GPS based timing for phasor measurement units using multi-receiver direct time estimation

Modern power distribution systems are incorporating Phasor Measurement Units (PMUs) to measure the instantaneous voltage and current phasors at different nodes in the power grid. These PMUs depend on Global Positioning Systems (GPS) for precise time and synchronization. However, GPS civil signals are vulnerable to external attacks because of its low power and unencrypted signal structure. Therefore, there is a need for the development of attack resilient GPS time transfer techniques to ensure power grid stability. To counteract these adverse effects, we propose an innovative Multi-Receiver Direct Time Estimation (MR-DTE) algorithm by utilizing the measurements from multiple GPS receivers driven by a common clock. The raw GPS signals from each receiver are processed using a robust signal processing technique known as Direct Time Estimation (DTE). DTE directly correlates the received GPS signal with the corresponding signal replica for each of the pre-generated set of clock states. The optimal set of clock candidates is then determined by maximum likelihood estimation. We further leverage the known geographical diversity of multiple receivers and apply Kalman Filter to obtain robust GPS timing. We evaluate the improved robustness of our MR-DTE algorithm against external timing attacks based on GPS field experiments. In addition, we design a verification and validation power grid testbed using Real-Time Digital Simulator (RTDS) to demonstrate the impact of jamming, meaconing (i.e., record-andreplay attack) and satellite data-level anomalies on PMUs. Later, we utilize our power grid testbed to validate the attack-resilience of our proposed MR-DTE algorithm in comparison to the existing techniques such as traditional scalar tracking and Position-Information-Aided Vector Tracking.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Aerospace Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2017

Author dc:creator

• Bhamidipati, Sri Ramya

Contributors dc:contributor

• Gao, Grace Xingxin

• Global positioning systems
• Phasor measurement units
• Timing attacks

Statement dc:rights

• Copyright 2017 Sriramya Bhamidipati

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/97515

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/97515