Developing a Guide for Transit Traction Power Cables (2024)
Chapter: 1 Introduction
Chapter 1. Introduction
1.1. Guide Structure
This guide was developed using the research results for ‘Replacement of Transit Traction Power Cables’. The guide includes a study of current practices for (1) assessing insulation aging (2) replacement of cables before failure, including (a) approaches used in transit systems for which there are no monitoring programs and/or testing systems (b) factors affecting the life of the cable, and (c) effective practices from transit agencies. In the research, a systematic review of the current literature was conducted, an assessment of status, and in-depth case studies identifying gaps and significant issues were developed to develop guidelines for the transit industry in the United States. The research aims to carry out a detailed cable life evaluation and develop an optimized process to evaluate the lifespan of cables to inform practitioners and provide solutions for their problems in the industry. The structure of the guide is shown in Figure 1.1.
First, an in-depth literature review and content analysis was conducted. The literature review focused on specific innovations, lessons learned, sound industry practices, and decision support. In addition, short-term, and long-term planning, setting of conditions and performance targets for cables, as well as cable performance evaluations, lifespan evaluations, investment planning, Transit Asset Management, allocation of risk and reward in the industry, and more were investigated. A synthesis of the existing literature was integrated with survey data to develop the guide. Data was gathered from several agencies through individual interviews and surveys in the data collection process. The information gathered was summarized for the guide, and critical information gaps were identified. Our team attended IEEE meetings, collected data from relevant practitioners in the field, and engaged with industry subject matter experts experienced in the design, construction, maintenance, and operation of traction power systems. Results of the survey were evaluated and statistically analyzed. Based on the survey results, ten case studies were developed to outline the cable maintenance practices of various types of transit systems. The guide was developed as demonstrated in Figure 1.2 including examples of strategies that seek to develop optimum and continuous solutions. Implementing an effective strategy and preparing an effective guide is essential to recommend optimum processes to design and implement solutions. An optimization model was established for the guide. Figure 1.3 presents work plan to develop the guide. Table 1.1 presents the Chapter Summary.
Table 1.1. Chapter Summary Chart
| Chapters | Titles | Summary | Parts |
|---|---|---|---|
| # 1 | Introduction | The guide was developed using the research results for ‘Replacement of Transit Traction Power Cables.’ The guide includes a study of current practices for (1) assessing insulation aging (2) replacement of cables. |
|
| # 2 | Answers to Key Questions | In this chapter, key questions were determined and answered. Literature review was carried out to respond the questions. Findings of the research works were classified under 8 parts. Research findings determine the lifetime and the replacement time spent in replacing underground cables. The estimated lifetime of the cables is around 35 to 40 years based on the experimental research results. To detect the failure in the cables, there are various test methods available. |
|
| # 3 | Survey/Interviews | The survey process was carried out in various locations. In the process, old, new, big and small systems were covered. Participants were selected from multiple locations to define their properties. |
|
| # 4 | Case Studies | Based on the survey results, ten different case studies were developed. Case studies were developed to demonstrate maintenance practices from a variety of systems (small, large, old, and new) by engaging industry subject matter experts experienced in the design, construction, maintenance, and operation of traction power systems. |
|
| # 5 | Cable Replacement | Cable Replacement was evaluated with optimization process and finite element analysis sections. For the optimization part, process was started with estimating the cable failure rates. The failure rate models can be estimated using historical failures. |
|
| # 6 | Conclusions | The guide presents practical solutions for the problems faced by the agencies. Problems and solutions created by the agencies are shared in the guide to share the best practices. Sections are designed to help practitioners to get an organized and systematic guide for the traction power cables. |
|
1.2. Research Approach
Research started with determining the key questions. These key questions are answered from literature review, survey/interview, and case studies. In Table 1.2, these key questions are provided. By answering these questions and understanding parameters effecting the cable life. Project aims to present the common practices and processes for use of transit traction power cables.
Table 1.2. Key Questions and Responses for Guide Development
| Q1 | How are we going to measure the degree of degradation? What is the industry standard for degradation? | Response- We need to set a measurement unit. For instance, if we consider a mile in a highway, the degree of degradation can be a composite unit that includes the area of potholes, the number of potholes, and distribution of depth of potholes. Similarly, a measurement unit should be defined for transit power cables. |
| Q2 | How long is the useful life of insulated cables? | |
| Q3 | What are the diagnostic indicators for when insulated cables should be replaced? | Response- We need to determine the current practice to avoid failures with an accurate indication of replacement considering cost/benefit trade off. Hence, we increase the lifetime of cables if we understand these reasons. |
| Q4 | What are the reasons for the cable to achieve its maximum useful life? | |
| Q5 | What are the reasons for the cable to degrade rapidly? | Response- We need to define the current environment and set a cost-effective construction environment for ‘smart replacement strategy’ and define the best characterization of “smart replacement strategy” for transit power cables. |
| Q6 | What are the keys for extending the useful life of insulated cables before the failure? |
Task Structure
Phase I: Guide Development
This phase of the project embraces the major steps in five tasks as depicted in Figure 1.4; a review of the state-of-the-art literature, an assessment of status, and in-depth case studies identifying gaps and major issues pertaining to develop a guide for the transit industry in the United States. Consequently, Phase 1 covers five tasks. The research was carried out for life evaluation of traction power cables for informing practitioners responding to the integrated and effective progress and their needs in the industry. Case examples of strategies that seek to develop optimum solutions for the needs of the industry while addressing opportunities and challenges that may affect decision making and asset management.
Task 1: Literature Review: An in-depth Literature Review and Content Analysis has been carried out in this first task to establish the ground for realistic evaluation. Literature review includes but not limited to processes, systems, and decision support with short-term and long-term planning, setting of conditions and performance targets for cables, performance evaluations, life evaluation, investment planning, Transit Asset Management, allocation of risk and reward among the sector, and more. The literature review has been mainly focused on matters that articulate specific innovations, lessons learned, and sound industry practices.
Task 2: Survey/Interview: A detailed information gathering from the sector through interviews and surveys to build an efficient guide. Survey tools were used to create an effective data gathering process. All available resources will be used for drafting the guide. The information gathered was summarized for the guide. Information gaps that are critical in nature were identified. IEEE meetings were beneficial for the team to meet the practitioners and collect data through the attendees. Survey results were analyzed, and a detailed investigation has been carried out.
Task 3: Case Studies: Based on the survey results, case studies were developed. Case studies were developed for covering maintenance practices from a mix of systems (small, large, old, and new) by engaging industry subject matter experts experienced in the design, construction, maintenance, and operation of traction power systems. Individual interviews were carried out in the selected locations for the case studies.
Task 4: Develop a Guide: Conducted literature review, information gathered and case studies with real examples helped the research team to formulate an appropriate strategy for drafting the guide. The guide was developed for implementing an effective strategy and preparing an effective guide to develop and recommend optimum processes to design and implement solutions. Based on the literature review, analysis of gaps in the literature, and summary of the information, the guide has been formed.
Task 5: Interim Report & Panel Review of the Developed Guideline: With the guideline development, an interim report was prepared for the panel review. In the submitted report, Phase I was explained and research details were given. Panel comments were received, and requested amendments were implemented into the guide.
Phase II: Training/Finalization
This phase comprises a training material and training sessions carried out with the research results gained in Phase 1. In Phase 2, guide was finalized. Training materials were developed, and training session was carried out. Figure 1.5. is presenting Phase II Research Plan.
Task 6: Create Training Materials
As the first task of the second phase, training materials were prepared. Problem-based learning approaches were used in the training sessions. Collected data from agencies, supporting the problem-based learning approach were used. Training materials were prepared to assist practitioners to understand the common practices, problems, and solutions created by the agencies. All training material were shared with the participants prior to the training sessions.
Task 7: Conduct Training Session
Training session was carried out to present the research findings. Developed guide was introduced and collected data was presented to the participants. At the end of the training session, a discussion session was run to discuss the participants’ responses to the initial survey. The survey results were compared with the research findings. Participants were asked to submit a feedback survey. The online training session was recorded and can be available online.
Task 8: Revise/Finalize the Developed Guide
The guide was finalized with implementing the panel comments. The panel recommendations were responded to, and all requests were considered precisely. Additionally, collected survey results from the training session was implemented in the survey study.
Task 9: Submit a Draft Final Deliverables/Final Research Report
Draft final deliverable was prepared and submitted for the panel comments. The comments were responded to and used for finalizing the guide.
Task 10: Address Panel Review Comments and Submit Final Deliverables
At the final stage of the project, all panel review comments were considered for the final version. At the final stage, final deliverables are (a) Final Report, (b) Guide, (c) Training Material, (d) Online Training Video Recording were submitted.
