On hydraulic calculations of a loop water distribution network
(to be discussed)

Summary

During the operation a loop water distribution network is subject to both disturbing impact and control activities. Disturbing impact aims at changing the state of the network. At that the operating personnel try to maintain the network in 100% working conditions at minimum costs by the control activities. Disturbing impact is caused by water consumption alterations and pipeline failures that arise stochastically. In the process of hydraulic designing water consumption variations are simulated with so called specific modes chosen at the most crucial moments of the water network operation. Hydraulic calculations of the specific modes are carried out provided the network is in complete function. The model of a loop water distribution network operation does not take into account the disturbing impact of failures. The construction rules and regulations determine only the level of the network operation in case of a single section cutoff. For simulating the process of failure occurrence and elimination the use of the mathematical tools of a queue system is suggested. The calculations show that at the existing water network failure rate and repair time the loop water distribution network is in non-operating condition at least for three and more weeks over a year. The procedure of hydraulic calculation of a loop water distribution network with account of occurring failures and repair time is suggested.

Key words

water consumption , hydraulic design , loop water distribution network , state of failure , repair time , regulating facilities

Calculation of loop network reliability

Summary

The reliability of loop water distribution network operation has been its primary property. However, until now the regulatory documents for designing water distribution networks lack the reliability indices. There is no consensus among the experts related to these indices. Earlier proposed set of reliability indices of a loop water network is considered and one of the possible methods of their calculation is suggested. The data on the time of the water mains 325.78 km long operating in serviceable and unserviceable conditions is set by the example of the Samara municipal water network (the data for 2014). For the theoretical determination of the time of the water mains being in serviceable and unserviceable conditions Markovian model was used with discrete states and continuous time. To decrease the dimensionality of the current task all the states with equal number of isolated sections were curtailed into one state (subset). The feasibility of this solution was prompted by the practice of water network operation. The model verification by Pearson’s Chi-square criterion allows accepting the hypothesis of the theoretical results corresponding to the available experimental data.

Key words

hydraulic design , reliability indices , loop water distribution network , Chi-square (Pearson’s) , Markovian model with discrete states and continuous time

Calculated parameters for the reliability of the ring water distribution network with account of the changed water consumption rate

Summary

The water distribution network of a community is part of the water supply system and provides for the distribution of water upon the facilities and supply of water to consumers. One of the main indicators of the operation of a water distribution network is its reliability. Boundary parameters of the reliability of the network operation can be considered the operating time of the network in normal and emergency conditions. Due to the decrease in actual water consumption in populated areas, the water consumption in sections of the water distribution network decreases; therefore, the reliability indicators of its operation also change. Besides, with the introduction of the revised edition of CP 31.13330.2021, the calculated values of the water consumption in the network have decreased significantly, since the water consumption rates have been reduced by more than 15%. In accordance with these data, the reliability indicators of the water distribution network were calculated.

Key words

hydraulic design , loop water distribution network , network operation reliability , reliability parameters , water consumption rate