Masters Theses


Mounika Chava

Keywords and Phrases

Demand Response; Distribution System


"High penetration of renewable energy resources such as rooftop solar photovoltaic (PV) systems is exacerbating violations of the voltage limits in power distribution networks. Existing solutions to these over-/under-voltage issues include tap-changing transformers and shunt capacitors. However, tap changers only allow voltage changes in discrete steps and shunt capacitors cannot handle over-voltage situations. To overcome these problems, this thesis proposes voltage control in a distribution system by adjusting active power loads. The proposed solution can be used for both under- and over-voltage cases at any levels of voltage adjustment. First, the active power that needs to be adjusted at selected nodes to bring the voltages within acceptable limits is calculated for under and over-voltage cases using alternating current optimal power flow (ACOPF). ACOPF is solved for three different cases by varying the cost of active power adjustment and the marginal cost from the feeder supply, which is assumed to be the market price. Secondly, demand response on electric water heaters is implemented to achieve active power adjustments at selected nodes obtained from the ACOPF results. The problem is formulated over multiple time steps to minimize the energy costs of water heaters at a specific node subject to the dynamics of the water temperature, the energy consumption, the temperature constraints, and the voltage limits at the node. The IEEE 34-bus radial distribution system is used as a case study. By solving the same problem for different price settings, it is observed that the price structure affects the energy demand only in the under-voltage system, but not in the over-voltage system. The main contribution of this thesis is to show that by adjusting active power loads, voltages in a distribution system can be maintained within the permissible limits"--Abstract, page iii.


Joo, Jhi-Young

Committee Member(s)

Crow, Mariesa
Shamsi, Pourya


Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering


Missouri University of Science and Technology

Publication Date

Fall 2016


viii, 40 pages

Note about bibliography

Includes bibliographical references (pages 37-39).


© 2016 Mounika Chava

Document Type

Thesis - Open Access

File Type




Subject Headings

Voltage regulators
Electric power distribution
Electric power systems -- Load dispatching
Electric power distribution -- Design
Electric power distribution -- Mathematical models

Thesis Number

T 11017

Electronic OCLC #