... rate of 0.36 mm/yr. Abstract A 2018 field investigation on an NPS 6, approximately 4 km long, liquid pipeline, identified a rectifier as the likely source of the elevated DC and AC current densities, which resulted in AC corrosion anomalies detected during in-line inspections (ILI). The findings...

...Abstract This paper presents a summary of the results obtained during 3 years of PhD studies on “AC Corrosion of Cathodically Protected Pipelines” at the Technical University of Denmark (DTU) ¹ , which was finalized in October 2018 and defended in January 2019. ¹ Amongst...

... installed in clay and operating at very low cathodic protection current. A three-year AC corrosion study ² indicated that the polarized OFF potential of fully protected coupons installed in clay dropped to an average of -638 mV_CSE, after application of the AC currents ¹...

...Abstract AC corrosion on cathodically protected pipelines is commonly experienced due to interference from high voltage transmission lines at a frequency of 50 or 60 Hz. In some cases, the source of interference may be low frequency AC transit systems (1/3 of the fundamental frequency...

...ABSTRACT Although a lot of AC corrosion failure cases have been reported on cathodically protected pipelines, the mechanism of AC corrosion process is still not completely understood and there has been a lack of technical consensus on AC corrosion mechanism under cathodic protection, especially...

... excavations, conducted an AC interference study, and developed an enterprise wide program focused on identifying, monitoring, and mitigating AC interference. The paper examines the results of each mitigative action and process adjustment taken by the operator. AC Corrosion ILI AC Interference Interference...

... recorded in this area, indicating a severe AC corrosion risk. Waveforms indicated that most of the AC voltage was 120 Hz frequency, and that very little of the AC voltage was related to the fundamental 60 Hz powerline frequency. This paper discusses the testing performed to confirm the source...

...AC Corrosion Test Vessel The AC corrosion test was performed in a large, H₂S-resistant, tubular vessel. The vessel contained about 40 L of test solution to provide a large volume-to-surface ratio ⁽³⁾ for the wire test specimens and adequate head-space for maintaining...

... the maximum touch and step voltage limits during momentary faults based on body weight, fault duration, 50Hz system frequency, and soil resistivity. The fault state safety criteria for this project are shown in Table 3 below. The pipeline integrity criteria for AC corrosion was based upon client...

... resistivity Longitudinal Electric Field (LEF) Electro-Magnetic Force (EMF) AC corrosion grounding computational modeling INTRODUCTION AC corrosion on pipelines has been well documented and researched for a number of decades. ^{1 , 2} More recently, standards like EN 15280-2013 “Evaluation...

...Abstract A field study was conducted to determine the influence of the AC current density and of the coating holiday size on the rate of AC corrosion. This field study involved burying steel coupons of three different sizes (i.e., 1 cm², 6 cm², and 10 cm²...

..., the integrity of the pipeline can be compromised as a result of accelerated AC corrosion and/or damage from a fault incident from nearby transmission line structures. AC interference levels can be predicted using a number of different methods including various field measurements as well as detailed computer...

..., e0 is the elementary charge of an electron and ∇ϕ represents the electric field. THE MODELLING PROCESS The parameters affecting AC corrosion described previously must be incorporated in a computer model, to evaluate and update over time using the equations described previously...

..., as per the ASTM ³ G1-03 standard, ²⁰ and the corrosion morphology of the surface was photographed again with an optical camera. The weight loss was measured with an Electronic Balance and the corrosion rate was calculated according to Equation (1) . Abstract AC corrosion...

...Abstract AC corrosion is dependent on both AC and DC current densities, but only little is known about the effect of the chemical environment. In this paper, laboratory soil-box experiments are made for a better understanding of the effect of specific chemical constituents in soil on corrosion...

... current corrosion on cathodically protected pipelines, updates to the AC corrosion mitigation design criteria, new materials and installation methods, and AC corrosion current density remote monitoring technologies. This paper presents a review of the design methods and mitigation technologies that were...

... and Na) and earth alkaline elements (mostly Ca and Mg) can precipitate as carbonates or hydroxides in high pH environments, but the earth alkaline elements form species of very low solubility [ 6 ]. Calcareous deposits will increase the spread resistance and limit the AC corrosion [ 7 ], but a thorough...

... road work was being completed in the area concurrently. The model predicted that the affected pipelines were expected to experience significant steady state, fault state, and AC corrosion interference issues prior to AC mitigation installation. The AC interference risk assessment, modelling, mitigation...

..., the wetland and environmental conditions made access with heavy vehicles extremely difficult. Abstract An AC interference study was conducted in 2015 following the installation of a new 240 kV powerline in a remote area of Alberta, Canada. The calculations indicated severe risk of AC corrosion...

... This paper details a comprehensive AC interference analysis and implementation of an extensive AC corrosion mitigation and monitoring system for a 100-mile (328 kilometer) portion of a regulated pipeline. The pipeline is collocated with multiple high voltage overhead AC power lines and countless adjacent...