Title page for ETD etd-05242005-212555


Type of Document Dissertation
Author Jun, Hwandon
Author's Email Address hwjun@vt.edu
URN etd-05242005-212555
Title Strategic valve locations in a water distribution system
Degree PhD
Department Civil Engineering
Advisory Committee
Advisor Name Title
Loganathan, G. V. Committee Chair
Kibler, David F. Committee Member
Lohani, Vinod K. Committee Member
Trani, Antonio A. Committee Member
Younos, Tamim Committee Member
Keywords
  • Segment
  • Performance Indicators
  • Failure Analysis
  • Simulation
  • Matrix Algorithm
  • Valve
  • Water Distribution System
Date of Defense 2005-05-06
Availability unrestricted
Abstract
Valves play a critical role in a water distribution system for subsystem isolation and flow or pressure control. Among them, subsystem isolation is required to repair or to rehabilitate a broken component and can be done by closing adjacent valves. To evaluate the role of valves, the concept of “Segment” is necessary. A segment consists of a set of pipes and nodes isolated together by closing adjacent valves when a pipe fails. An efficient algorithm to identify segments in a water distribution system is proposed. In addition, when a segment is isolated, an additional subsystem may be disconnected from water sources by the segment isolation. It is a topological unintended isolation. In addition, a hydraulic failure, in terms of pressure types of failures at demand nodes should be considered. These three account for the failure impact of a pipe.

Placing valves efficiently improves the reliability of a water distribution system. However, the valve reliability itself is not 100%. Therefore, valve failure consequence should be explored in determining the locations of valves. For this purpose, three methodologies, namely segment-valve matrix algorithm, decision tree approach and simulation are proposed. Another consideration for placing valves is a strategic valving rule, namely N and (N-1) valving rules. Using a formulation for node reliability in terms of failing valves, the reliability difference between the two valving rules is evaluated. We also employ a mixed N and (N-1) valving rule. Another strategic valving rule, a segment size reducing approach minimizing the number of affected customers is proposed.

The developed algorithms are utilized to build software, the Strategic Valve Management Model, to solve practical problems. The methodology is applied to three real water distribution systems.

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