Cable Installation Research Articles

Инновационный процесс в Арктике: мировые тенденции и актуальные российские проблемы

The pursuit of innovation-driven growth in the Russian Arctic aligns with global trends associated with the advent of a new Kondratieff cycle, which spurs demand for groundbreaking technologies. This article aims to identify significant trends and challenges related to innovation in the Arctic that require focused attention and further research. The concept of national and regional innovation systems serves as the theoretical framework, with a selective comparative study of Russian and international practices as the primary research method. Our analysis demonstrates that Russia lags behind the majority of Arctic nations in terms of innovation ratings, including the quality of institutions, the structure of the economy, and infrastructure development. Research and industrial policy priorities remain unclear. Innovations enter the Russian Arctic through large-scale projects within extractive industries, which rely on imported technologies and raw material exports. However, as Norway’s experience proves, these projects can leverage the research and production potential of the North if government support is provided. The article addresses corporate challenges associated with digitalization in the Arctic using fiber cable installation as a case study. Currently, the only operational lines are the line located off the Alaska North Slope and the first leg of the Russian Polar Express line, which provides Russia with an important competitive edge. We conclude that the government should play a crucial role in promoting innovations in the Russian Arctic, acting through state-owned enterprises, public agencies, and subsidized private entities. The novelty of the study lies in addressing phenomena that have received insufficient attention in Russian research while considering international practices. The practical relevance of the study lies in its potential application to strategic planning for innovation-driven growth in the Arctic. Further research should seek to identify and closely study specific challenges of the Russian Arctic innovation system in comparison with international best practices in order to provide concrete practical recommendations.

Small effect sizes are achievable in offshore wind monitoring surveys

Abstract Understanding the prospective environmental impacts of offshore wind energy development requires monitoring that allows for adequate testing of conditions for comparison of unimpacted vs. impacted states. A critical component when designing impact studies is determining the required sampling needed to statistically measure a difference between before and after states in the system, which is often challenging because there are little observational data available for the system of interest at the proper spatiotemporal scales. Here, we present the survey design with power and effect size analyses that were used to design a before-after gradient survey to assess American lobster impacts from an offshore wind submarine cable installation in coastal United States waters. By leveraging long-term monitoring data collected from a random-stratified sampling design survey, a gradient survey testing for effects on lobster at distance intervals from the cable using similar sampling methods was developed. Generalized linear mixed models were employed to determine the needed sampling frequency to assess varied catch-per-unit-effort impacts. We present the survey design and our findings from the power analyses to serve as an example of methodology for designing before and after impact surveys for offshore wind energy, and how preexisting data may be used to do so.

Development of a New Model for the Formation of Wax Deposits through the Passage of Crude Oil within the Well

Wax deposits related to flow assurance are a costly problem in oil production in many fields around the world. Modeling of this process is the main tool for creating and optimizing methods to deal with this problem. This paper considers a new empirical model for the formation of these deposits, based on the results of an array of laboratory studies, theoretical data and technological calculations are presented. The created technique takes into account the conditions of oil flow, data from laboratory studies, and the water cut of the product. The experience of the industrial operation of the technique showed a high convergence of the calculated and actual deposit profiles. Based on a comparison of the calculated and actual deposit profiles, it was concluded that the standard deviation of maximum wax thickness is 6.0%, and the depth with the greatest wax thickness is 3.5%, which is a fairly high result. The use of this technique makes it possible to optimize the depth of mechanical cleaning of the well, the installation of heating cables, as well as the parameters of hot flushing, which increases their efficiency and reduces the cost of combating the formation of wax deposition.

Influence of Water Content on the Dielectric Characteristics of LN2-Impregnated PPLP for HTS Power Cables

High-Temperature Superconducting (HTS) power cables operate at low, medium, and high voltage levels for electrical power transmission. Polypropylene Laminated Paper (PPLP) is wrapped helically around the HTS layer and it is impregnated with Liquid Nitrogen (LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) to form a composite dielectric layer. During the installation and maintenance process of HTS cables, any leak of moisture in the cryostat will lead to immediate ice formation. Once the cable warms up, the ice will melt into water, which will be absorbed by the PPLP Kraft paper layer and is similar to the PPLP paper soaked with water. When the moist PPLP is cooled with LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> it will form ice and forms a composite material during operation. The objective of this paper is to investigate the influence of water content on the breakdown strength, relative permittivity (ϵ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> ) and dielectric losses of LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> impregnated PPLP samples for different number of layers. Considering the worst-case scenario of moist samples, wet PPLP samples were tested for breakdown strength and dielectric properties at Room Temperature (RT) and LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> temperature and was compared with dry PPLP samples. Two different experimental setups were developed to measure the breakdown strength and dielectric properties respectively for stacked PPLP layers. The wet and dry samples were tested for the AC V-I characteristics, the effect of PPLP stack thickness on dielectric strength, statistical analysis using two parameter Weibull distribution and computation of relative permittivity and loss factor from capacitance measurement.

Dynamic analysis of the umbilical cable pull-in operation through J-tube under different wave directions

Pipelines and cables are widely used for transporting oil resources in offshore oil exploitation. J-tubes are a well-known means of placing small-diameter pipeline risers and umbilical connections on offshore platforms. In this paper, OrcaFlex develops a model of an umbilical cable J-tube pull-in installation based on an umbilical cable cross section design. The hydrodynamic response to various wave directions is studied using the lumped mass method. The results show that the longitudinal waves have little effect on the maximum effective tension of the section under water. The transverse waves will cause the cable to vibrate violently in the transverse direction. The mean shear force under the wave direction of 120° is the largest, followed by 60° and 75°, and finally 90° and 105°. In addition to the hydrodynamic response data, the mechanical characteristics of the umbilical cable and the factors that should be considered in the pull-in installation of the J-tube are provided with significance for practical application of engineering.

Rapid Surface Deployment of a DAS System for Earthquake Hazard Assessment

Distributed acoustic sensing (DAS) is a relatively new technology used in many geophysical applications. The versatility, high spatiotemporal resolution, and sensitivity to surface waves make DAS ideal for rapid deployment surveys such as earthquake-aftershock monitoring and hazard assessment. However, these applications usually rely on trenched cable installations that are time consuming and cost-prohibitive to deploy, or on existing telecommunication fibers that are limited in spatial coverage. To examine the potential of untrenched surface deployments, we acquired DAS data in continuous mode for one hour on a rapidly deployed fiber array composed of six parallel linear subsections directly on the surface with different fiber-ground contact conditions. We applied ambient interferometry and adopted a simplified method to determine the average shear-wave velocity of the top 30 m (VS30). Our methodology resulted in robust VS30 estimates for each surface deployment subsection that are consistent with collocated 1-m-deep trenched cables. The implications of these findings support DAS as a viable method for noninvasive-deployment surface surveys for rapid earthquake hazard and damage assessment.

Interpretation of Fracture Initiation Points by In-Well Low-Frequency Distributed Acoustic Sensing in Horizontal Wells

Summary Low-frequency distributed acoustic sensing (LF-DAS) exploits the optical phase shift of Rayleigh backscatter in fiber-optic cables to obtain distributed measurements of changes in strain and temperature. Fiber-optic cables are often installed for multistage hydraulic fracture diagnostics in horizontal wells. LF-DAS in an untreated well provides far-field strain measurements, while offset wells are hydraulically fractured. Such a configuration is called crosswell LF-DAS sensing. Crosswell LF-DAS measurements have proved useful in diagnosing fracture hits, fracture azimuth, planarity, cluster efficiency, fracture propagation rates, and the dynamic distance to the fracture front. In contrast, in-well LF-DAS is conducted on the actively fractured well. Due to cool fracture fluid being injected at high injection rates, the strain component of the LF-DAS response is largely obscured by temperature changes. In permanent fiber-optic cable installations, distributed temperature sensing (DTS) is often conducted simultaneously with LF-DAS. An opportunity exists to decouple the temperature and strain components of LF-DAS sensors to observe strain changes on in-well LF-DAS. The LF-DAS response is modeled as linearly dependent on strain and temperature changes. Theoretical LF-DAS temperature and strain sensitivity coefficients are derived based on the changes to the index of refraction and length of the fiber. Using the DTS measurements, temperature changes are computed, smoothed, filtered, and compared to the LF-DAS response. Crossplots of the in-well LF-DAS measurements and temperature changes from DTS measurements far from the actively fractured region are used to validate the theoretical sensitivity coefficients. Uncertainty in the temperature component of the LF-DAS response is quantified. The difficulty in corresponding the different spatial and temporal resolutions of the DTS and LF-DAS measurements is overcome by comparing the responses over a moving temporal and spatial window. If the LF-DAS response at the center of the window agrees with the DTS response within uncertainty, the measurement is filtered out. After filtering, the remaining nonzero in-well LF-DAS measurements are due to changes in strain. The data are then visualized in waterfall plots. The results indicate that the theoretical and observed strain and temperature coefficients agree within 10%. After the temperature component of the in-well LF-DAS response is extracted, the remaining nonzero measurements are located primarily within the actively treated region. Locations with peaks in the strain response are interpreted to indicate fracture initiation points. These fracture initiation points are compared with in-well DTS and high-frequency DAS noise measurements across multiple stages to better understand fracture initiation along the horizontal well.

Practical Approach to Underground Distribution Power Cable Fleet Management

With the growing requirements imposed by regulatory authorities, grid operators and power utilities firms are confronted with the challenging task of ensuring the reliability, safety, and resilience of distribution networks amid aging asset infrastructure and a lack of resources. Over the past 15 years, the health index (HI)-based analysis has become an increasingly popular asset management tool for several power utilities. This strongly focuses on HI-based analysis to consider not only factors such as the cable vintage, type, and operating conditions, but also maintenance testing data. In this regard, the best industry practices for cable maintenance testing, including VLF Tan-Delta, partial discharge (PD), and time domain reflectometry (TDR), are outlined. Moreover, online tests, such as infrared thermography, ultrasonic PD scan, and temperature monitoring, are discussed. This paper also summarizes the classic asset management strategies for underground (UG) distribution power cables. The paper offers a practical approach for cable fleet management based on authors’ experience dealing with distribution power utility cable management for North American power utilities firms in the past 10 years. The proposed approach ensures reliable cable management at the lowest total life cycle cost. The topic of fleet management for UG power cables considering various condition parameters and an overall risk assessment is outlined. The fleet management guideline of UG power cables covers both cables and their accessories, such as terminations and joints. The main contributions of the paper are to: (1) determine the key parameters and testing factors for condition assessment of cables; (2) offer a practical approach to cable management that is not only based on technical issues, but also considers risk and impact costs, such as financial impact, reliability impact, etc.; and (3) propose a methodology for translating the HI/calculated risks into GIS, making it possible to identify major degradation patterns for fleet assessment. Considering budget and resource limitations around testing UG cable installations, this paper aims to assist asset managers, engineers, and asset owners in developing an effective cable fleet management strategy.

Techno-economic study of very dense optical wireless access using visible or infrared light

Future wireless networks need to serve a high density of end-user devices with a high quality of service. The density of wireless access points and the infrastructure behind them lead to substantial cost. We study this cost impact for the particular case of optical wireless communication [also denoted as light fidelity (LiFi)] in a large manufacturing hall. We compare different LiFi network topologies using visible or infrared light. Considering aspects such as the fronthaul cabling layout, equipment investments, and installation and operational costs for energy and maintenance, different LiFi solutions are analyzed for greenfield and brownfield scenarios. The techno-economic analysis is performed in terms of total cost of ownership as well as the impact of each cost category to the final cost. Furthermore, the cost per delivered Mbps is compared to take into account the expected densification (more bits/s/m2) and satisfy the demand for future wireless traffic. Both delivered capacity and power consumption have been identified as the two most critical parameters.

Dynamic Characteristics of Rock Holes with Gravel Sediment Drilled by Bit Anchor Cable Drilling

Gravel and sediment frequently build up in holes during the anchor cable installation process, which makes it harder to install the anchor cable and causes reinforcement to fail, which can lead to accidents. In this paper, a bit anchor setup approach is proposed to set up a drill bit at the front of the anchor cable to aid the anchor cable drilling. The feasibility of this approach is established with the aid of DEM-MBD joint simulation and proves the correctness of the simulation model. The major elements affecting drilling effectivity have been studied by the use of ‘check + simulation’. The effects exhibit that the axial velocity and working aperture are negatively correlated with the drilling resistance of the anchor cable; the feed price is positively related to the anchor cable drilling resistance; with the increase in anchor cable pitch, the drilling resistance of the anchor cable changes into a hump shape. When the bit is 0.2 m from the backside of the hole, the particle pace vector at the decrease stop of the bit gives a conical distribution. This paper is of fantastic magnitude in relation to the environment-friendly setup of anchor cables and protection against disasters.

Determination of the Physical Integrity of Ethernet Cables by Obtaining their Transmission Line Parameters from Measured Impedance Profiles

A method of determining the physical integrity of Ethernet cables by obtaining their transmission line parameters (resistance, inductance, capacitance, and conductance) from their measured impedance profiles are presented. The transmission line parameters were extracted across the cable lengths rather than frequencies used in most research. The method can be used to examine the physical integrity of Ethernet cables before their deployment. The study of the physical integrity of Ethernet cables is very important because, in typical installations, cables can be manipulated in the form of repeated coiling and uncoiling. The installation handling stress can adversely affect the signal integrity especially if they are substandard Ethernet cables. In this paper, four Ethernet cables were subjected to three coiling and uncoiling tests to represent installation handling stress. The impedance profiles of the four cables across their lengths were measured for the three handling stress test conducted. The computation of the transmission line parameters of the Ethernet cables using measured impedance profiles was implemented with the aid of Matrix Laboratory (MATLAB). The outcome of the research showed that the method presented will be very useful to cable installers and contractors in making objective decisions in the choice of cables for deployment.

Design and Evaluation of Capacitive Smart Transducer for a Forestry Crane Gripper

Stable grasps are essential for robots handling objects. This is especially true for "robotized" large industrial machines as heavy and bulky objects that are unintentionally dropped by the machine can lead to substantial damages and pose a significant safety risk. Consequently, adding a proximity and tactile sensing to such large industrial machinery can help to mitigate this problem. In this paper, we present a sensing system for proximity/tactile sensing in gripper claws of a forestry crane. In order to avoid difficulties with respect to the installation of cables (in particular in retrofitting of existing machinery), the sensors are truly wireless and can be powered using energy harvesting, leading to autarkic, i.e., self-contained, sensors. The sensing elements are connected to a measurement system which transmits the measurement data to the crane automation computer via Bluetooth low energy (BLE) compliant to IEEE 1451.0 (TEDs) specification for eased logical system integration. We demonstrate that the sensor system can be fully integrated in the grasper and that it can withstand the challenging environmental conditions. We present experimental evaluation of detection in various grasping scenarios such as grasping at an angle, corner grasping, improper closure of the gripper and proper grasp for logs of three different sizes. Results indicate the ability to detect and differentiate between good and poor grasping configurations.

INVESTIGATION OF PSK/QAM MODULATED HYBRID FIBER OPTIC AND FREE SPACE OPTIC SYSTEM UNDER VARIOUS ATMOSPHERIC LOSSES

This research aims to investigate how effectively digital modulation performs to transfer data via hybrid fiber optic and free space optic (FO-FSO) channels for last-mile communication systems. Digital modulation techniques investigated are phase-shift keying (PSK) 8-PSK, 16-PSK, quadrature amplitude modulation (QAM) 4-QAM, 16-QAM, and 64-QAM. FSO is line-of-sight technology being a solution to a last-mile communication system for the challenge of fiber optic cables installation. Combining FSO with fiber optic technology avoids bending losses and the implementation challenges of fiber optic cables in metropolitan areas and between buildings. But atmospheric challenges such as haze, fog, and rain cause signal loss while transmitting data in free space. Also, atmospheric turbulence and antenna misalignments lead to signal error. This paper proposed the models of QAM and PSK digital modulated signal transmission over FO-FSO and compared the results to better fiber optic-FSO links to achieve a last-mile communication network. This fiber optic and FSO model is analyzed for the distance up to 100 km of fiber optic channel and 0.4-1.5 km of FSO channel. Constellation diagrams and error-vector magnitude (EVM) concerning received power at the receiver are compared to analyze FSO channel capacity for various weather attenuations.

Study on the Dynamic Characteristics of Bit Anchor Cable Drilling in the Gravel Sediments of a Soft Rock Bottom Hole

During the pore-forming stage of floor heave treatment, the phenomenon of gravel sediment accumulation in the bottom hole often occurs, which causes great difficulties in the normal installation of the anchor cable. Based on this observation, a new anchor cable installation method was proposed, which involves installing a drill bit at the front end of the anchor cable to assist its drilling. With the help of an anchor cable drilling test bench, the influence of the bit, motion parameters, and hole environment on the performance of anchor cable drilling was studied. Through the co-simulation of the discrete element method (i.e., multibody dynamics (DEM-MBD)), the drilling process of the bit anchor cable was simulated, and the dynamic characteristics of the bit anchor cable drilling in the bottom hole gravel sediment were analysed. The results show that installing a drill bit in front of the anchor cable can greatly reduce the drilling resistance and hamper torque during anchor cable drilling. When the rotational direction of the bit anchor cable is consistent with the spiral direction of the anchor cable, the bit anchor cable can exhibit better drilling performance. The drilling resistance and hindering torque of the bit anchor cable are the largest when drilling in soaked particles, followed by drilling in dry particles, and the smallest occurs when drilling in moist particles. The research results can provide reference for the parameter setting of anchor cable auxiliary installation equipment.

Aerodynamic Characterization of the 516 Arouca Pedestrian Suspension Bridge over the Paiva River

Given the 516 Arouca pedestrian suspension bridge’s design and characteristics, the owner, a municipality, required a set of tests in order to evaluate its aerodynamic characteristics and dynamic response, aiming at both structural safety and user comfort. Wind tunnel tests were performed over a sectional scaled model to obtain the static aerodynamic coefficients and dynamic response. The tests were carried out on different bridge configurations—a deck with people and a deck with an arch for secondary cables (connecting each suspension point to the catenary on the opposite side of the deck)—for the static coefficients. For the dynamic response, only the deck alone was tested. A major challenge had to be overcome, as the main displacement mode belonged to a swing movement, to assemble a wind tunnel setting, requiring a suspension system allowing wind displacements. A persistent trend of small amplitude displacements was identified, influencing user comfort and contributing to the installation of the secondary cables, but no aerodynamic instabilities were identified.

Charge transport mechanism of cross‐linked polyethylene/silicone rubber composite insulation by energy band theory

AbstractThe composite insulation composed of cross‐linked polyethylene (XLPE) and silicone rubber (SiR) is common in high voltage direct current cable accessory installation. However, the space charge accumulation, especially the interfacial charge accumulation of XLPE/SiR, poses a serious threat to the safe operation of cable accessories, and its charge transport mechanism is still unclear, especially at the micro‐scale. In order to investigate the charge transport mechanism of XLPE/SiR, simultaneous measurement of space charge and relaxation current is performed on XLPE/SiR at various electric fields with different polarities, and the electronic energy levels of XLPE and SiR are determined by quantum chemical calculation (QCC). The results of QCC show that both the hole traps and the electron traps in XLPE are mainly shallow traps. As for SiR, the hole traps are shallow traps, while the electron traps are deep traps. The results of simultaneous measurement show that the interfacial charge accumulation and the composite conductivity of XLPE/SiR are significantly different under different polarities, that is, there is an obvious polarity effect. Based on the results of QCC, the electronic energy levels of XLPE/SiR system are constructed considering the interface between XLPE and SiR, as well as the interfaces between the materials and the electrodes. On this basis, the charge transport mechanism of XLPE/SiR is discussed in detail, and the polarity effect is well explained, which is believed to be related to the differences in the charge injection barrier and the interfacial barrier under different polarities, as well as the electron/hole traps in XLPE and SiR.

Full-scale installation trial of ITER's in-vessel and marshalling area loom prototypes

The in-vessel components of the ITER Diagnostics are located all over the inner shell of the Vacuum Vessel, in the Ports and on the Divertor Cassettes as well. The electrical transmission lines which transmit the signals from the sensors across the vacuum boundaries are Mineral Insulated Cables. These cables will be arranged into looms, which will be fixed to the vacuum vessel with different kinds of attachments.The ITER tokamak is at a stage where manufacturing and testing of each component are becoming more and more important. For this reason, to allow IO to assess feasibility, gain experience and obtain feedback with respect to the suitability of the current designs regarding handling and installation of in-vessel signal cables and loom components, GEMS Engineering has carried out a series of installation trials on full-scale mockups of in-vessel and divertor looms, upper and lower port marshalling area looms. Beside of installation trials, the scope of the work also covered the manufacturing and testing of cable clamps and clips for in-vessel and divertor looms and marshalling areas.This paper outlines the results of the manufacturing of prototypes and assembly trials of the above-mentioned components.

Mechanism of shear strengthening for RC beam by drilling web openings based on experiment and 3D RBSM analysis

In practice, web openings are usually drilled in reinforced concrete (RC) beams to accommodate pipes and cable installations. But introducing web openings always causes shear degradation of RC beams. This study aims to establish a rational position design of multiple small web openings, which can improve the shear behavior of RC beams, by controlling the path of critical diagonal crack. Three-point bending tests on four RC beams without and with web openings (shear span depth ratio: 2.59 and 3.56) were firstly carried out to evaluate the strengthening effect attributed to the proposed placement of web openings. Besides, the Three Dimensional Rigid-Body-Spring Method (3D RBSM), a discrete numerical methodology, was applied to simulate the test process, and the strengthening effect due to the placement of web openings was parametrically investigated. Finally, the decoupling of shear components (beam and arch actions) was conducted to comprehensively understand the shear strengthening mechanism due to drilling web openings, by using RBSM-based methodology. The test and numerical results confirmed that the proposed position design of web openings could evidently improve the shear strength and deformation ability of RC beams, because the multiple web openings could increase the angle of critical diagonal crack, by predetermining it propagation path. Moreover, it was clarified that the strengthening mechanism of shear behavior owing to web opening setting was dependent on the more dramatic development of arch action with the increasing angle of critical diagonal crack. The present paper provided a rational design to solve the problem of shear degradation caused by small web openings in the field of concrete member design, and proved a possibility to strengthen the shear behavior of existing concrete beams by drilling web openings.

Geological and geotechnical characterisation of soft Holocene marine sediments: A case study from the north Irish Sea

The seabed of the Western Irish Sea Mud Belt (north Irish Sea) comprises a thick sequence of fine-grained Holocene marine sediments that overlay complex glacial deposits. The Holocene sequence preserves a record of environmental change in the area. Part of this area is earmarked for a number of offshore wind farm developments. The area poses a number of geotechnical challenges to such developments, including soft marine silts and clays as well as shallow gas. This paper characterises the soil conditions in the area in the context of offshore renewable energy development using various geophysical techniques, geotechnical data and shallow (3 m) sediment samples obtained across multiple research surveys between 2009 and 2020. The purpose is to assess the use of such techniques, including multichannel sparker seismic and underwater multichannel analysis of surface waves (UMASW), in characterising these kinds of sediments. It is also intended to build on previous research and provide a reference dataset and case study for further work in developing offshore wind in the area. UMASW and in-situ cone penetration testing with pore pressure measurement (CPTu) results showed good agreement in characterising these Holocene sediments, with multichannel sparker delineating shallow gas from surrounding sediments. Core profiles show distinct lithological variation in the upper 3 m, which can be related to CPTu parameters, but is not resolvable by UMASW profiles. Paleoenvironmental reconstruction for this upper 3 m suggests changes in depositional setting over the past ca. 7000 years, which could influence sedimentary structure. These parameters have implications for cable installation design.

Concerning partial discharge detection in cable lines using high-frequency sensors

Partial discharges result in cable line faults that can occur in defective insulation systems made of rubber, polyethylene, XLPE, and flexible PVC. Insulation defects may occur due to disruptions in their production process, cable installation, and operational conditions. Therefore, the diagnostic and monitoring of partial discharge occurrence in cable insulation help prevent emergencies in damaged cable line sections. Partial discharge registration is a non-destructive diagnostic method that helps assess the cable line condition and localize the detected defects. There are various methods of operational monitoring and partial discharge cause analysis based on operative partial discharge sensors. The assessment of cable line condition depends on the efficiency of signal detection and processing by the sensors used. This article reviews the problems of detecting and localizing partial discharges in cable lines and junction boxes using HFCT and UHF sensors. Having analyzed the capabilities of these sensors, we believe that the combined usage of HFCT and UHF sensors is the best method of detecting and localizing partial discharge within the entire cable system (lines and junction boxes).