The Performance of a Passive Autoranging Method for a Photonic Current Transducer.

This paper reports on the testing and evaluation of a passive autoranging (AR) method designed to dynamically extend the measurement range of a photonic current transducer (PCT) to pave the way toward a realization of a combined metering- and protection-class current sensor. The PCT utilizes a current transformer (CT), a piezoelectric transducer (PZT), and a fiber Bragg grating (FBG) to enable current measurement at multiple points in an electrical power network whereby multiple sensors are deployed and interrogated serially using a single optical fiber. The autoranging technique relies on incorporating static MOSFET switches to instantaneously short individual serially connected CT burdens in response to a measured current magnitude exceeding pre-set thresholds.

Design and Implementation of a Passive Autoranging Circuit for Hybrid FBG-PZT Photonic Current Transducer.

In this paper, we present a novel technique for passively autoranging a photonic current transducer (PCT) that incorporates a current transformer (CT), piezoelectric transducer (PZT) and fiber Bragg grating (FBG). Due to the usage of single-mode fiber and FBG, multiple PCTs can be interconnected and distributed over a long distance, for example along a power network, greatly reducing the cost of sensor deployment and offering other unique advantages. The autoranging technique relies on the usage of multiple, serially connected CT burden resistors and associated static MOSFET switches to realize instantaneous shortening of the resistors in response to increasing measured current.

Construction and Evaluation of an Optical Medium Voltage Transducer Module Aimed at a 132 kV Optical Voltage Sensor for WAMPAC Systems.

This paper reports on the construction and characterization of an optical voltage transducer module for applications in the field of wide-area monitoring, protection, and control (WAMPAC). The optical medium voltage transducer (MVT) module was designed to be combined with a capacitive voltage divider (CVD) to form a voltage sensor intended for 132 kV high voltage (HV) networks. The MVT module comprises a combination of a piezoelectric transducer (PZT) and a fiber Bragg grating (FBG) as a core optical sensing element.

Photonic Voltage Transducer with Lightning Impulse Protection for Distributed Monitoring of MV Networks.

The design, construction and characterization of a photonic voltage transducer with a lightning impulse protection for distributed measurements on medium voltage (MV) networks (11 kV) was presented in this paper. The sensor prototype, comprising a combination of a piezoelectric transducer and a fibre Bragg grating (FBG) as a core optical sensing element, and a dedicated lightning protection device comprising a set of reactive components, was evaluated through laboratory testing and its performance was assessed based on the accuracy requirements specified by the relevant industry standards. It was demonstrated that the sensor has the potential to meet the accuracy requirements for the 3P protection and 0.

Heterotopic ossification and clinical results after total hip arthroplasty using the anterior minimally invasive and anterolateral approaches.

Introduction: Total hip arthroplasty (THA) is considered the gold standard in the treatment of advanced osteoarthritis of the hip. The aim of this study was to compare the incidence of heterotopic ossification (HO), the quality of life and the function in two groups of patients who underwent total hip arthroplasty (THA), performed using the anterior minimally invasive (MIS) and the anterolateral approaches.

Material And Methods: Retrospective analysis of 597 patients who underwent THA in 2009-2013 was performed.

Field Demonstration of Real-Time Wind Turbine Foundation Strain Monitoring.

Onshore wind turbine foundations are generally over-engineered as their internal stress states are challenging to directly monitor during operation. While there are industry drivers to shift towards more economical foundation designs, making this transition safely will require new monitoring techniques, so that the uncertainties around structural health can be reduced. This paper presents the initial results of a real-time strain monitoring campaign for an operating wind turbine foundation.

Wireless Concrete Strength Monitoring of Wind Turbine Foundations.

Wind turbine foundations are typically cast in place, leaving the concrete to mature under environmental conditions that vary in time and space. As a result, there is uncertainty around the concrete's initial performance, and this can encourage both costly over-design and inaccurate prognoses of structural health. Here, we demonstrate the field application of a dense, wireless thermocouple network to monitor the strength development of an onshore, reinforced-concrete wind turbine foundation.

Crack Monitoring of Operational Wind Turbine Foundations.

The degradation of onshore, reinforced-concrete wind turbine foundations is usually assessed via above-ground inspections, or through lengthy excavation campaigns that suspend wind power generation. Foundation cracks can and do occur below ground level, and while sustained measurements of crack behaviour could be used to quantify the risk of water ingress and reinforcement corrosion, these cracks have not yet been monitored during turbine operation. Here, we outline the design, fabrication and field installation of subterranean fibre-optic sensors for monitoring the opening and lateral displacements of foundation cracks during wind turbine operation.