La política industrial y empresarial en el medio rural

Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Peradeniya

Novel technologies are expected to be incorporated into today’s power grid to enhance its functional capabilities while providing increased customer satisfaction through a sustainable power network. Thus, future power networks are expected to incorporate large amount of Distributed Renewable Energy Resources (DRER) while maintaining power quality. Smart grid, which is based on microgrid, is expected to serve these requirements.

However, the intermittent and random nature of DREG, like wind and solar could destabilize the network as conventional power control systems cannot handle high frequency fluctuations. Hence, a high frequency power fluctuation has to be mitigated within the microgrid. Such power balancing algorithm-based diverse optimality criterion has been presented in many papers. However, voltage in the distribution feeder is affected due to variation in power flow. In order to guarantee the power quality, the voltage in the distribution feeder should be maintained within the standard tolerance level. When it comes to smart grid where multiple DREGs are pumping power into the grid at various nodes of the feeder, a fluctuating voltage profile results.

In this paper we have presented a way to incorporate voltage constraints into power balancing schemes with minimal changes to the conventional distribution network. In this study, a 33kV distribution feeder with four 33kV/400V transformers (node) is considered. The aggregated models of wind, solar PV, Combined Heat and Power (CHP), Electric Vehicles (EV), controllable loads and uncontrollable loads below 33kV/400V transformer are combined to represent a node. Voltage tolerance of ± 2% was included into an existing power balancing scheme and the simulation results are shown in Figure 1. It can be seen in the figure that voltage of the feeder was always maintained within the limits. It can also be noticed near t = 0 s, t = 183600 s and t = 194400 s, that the Load Tap Changer (LTC) is switched to maximise the solution space of the optimization algorithm.

Figure 1. Variation of voltage in each node

0 0.5 1 1.5 2 2.5 3 x 105 32.4 32.6 32.8 33 33.2 33.4 33.6 time(s) (k V )

Voltage variation at node 1

0 0.5 1 1.5 2 2.5 3 x 105 32.4 32.6 32.8 33 33.2 33.4 33.6 time(s) (k V )

Voltage variation at node 2

0 0.5 1 1.5 2 2.5 3 x 105 32.4 32.6 32.8 33 33.2 33.4 33.6 time(s) (k V )

Voltage variation at node 3

0 0.5 1 1.5 2 2.5 3 x 105 32.4 32.6 32.8 33 33.2 33.4 33.6 time(s) (k V )

Voltage variation at node 4 183600 s 194400 s

Proceedings of the Peradeniya University Research Sessions, Sri Lanka, Vol. 16, 24th _{November 2011}

31

Text Message Service Based Home Care System

R.M.N. Rathnayake, A.M.S.B. Alahakoon, H.P.N. Madhubhashini, and K.M.M.W.N.B. Narampanawe.

Department of Electrical and Electronic Engineering, Faculty of Engineering University of Peradeniya

In the modern world, house robbery has become a great issue. Relevant authorities face difficulties in giving reasonable solutions for this problem. In this paper we propose a cost-effective permanent solution for home security with some advanced features. The system is based on GSM network and a sensor and actuator network. The developed system can be used to control and monitor the user’s house through mobile phones.

There are four main parts of this system. They are: the controlling circuit on a microcontroller platform; the sensor and actuator network; GSM communication equipment; and the user’s mobile phone. The implemented sensor and actuator network has sensors such as proximity sensors, gas sensors and read switches. Further, in some actuators, relays to turn on/ off any device and audible alarms are present. The control system utilises 5v regulator output which draws the maximum 100 mA without actuators.

The user is informed by a SMS when a security or other issue (for example, fire or gas leak) arises. The system will simultaneously send SMSs to relevant authorities like the police station or fire brigade. The user can always control the devices in the house by sending a SMS to the control unit and the user will receive an acknowledgement from the controller. As an example, the user can provide commands to switch on/ off devices such as water pump, bulbs, TV etc. and receive acknowledgments. The system updates the user within a maximum of two seconds on each and every task. Furthermore, a J2ME user interface was developed to use in the mobile phone of the user.

Even though the concept has been developed for home automation, it is possible to use the same scenario for various applications. For example, in a control system, it is necessary to send references and get feedbacks. The developed system can be used to receive current status (feedbacks) of the control system and send control commands (references) to it. By combining the GSM section with a GPS receiver, a tracking system can easily be developed for fleet management, animals, stock maintainence etc. For these applications, a computer interface can be developed between the computer and the control circuit via serial port communication.

These research outcomes are especially useful for low-cost automation systems as all the GSM service providers provide GSM service at a very low cost. Considering all aspects, the Short Message Service Based Automation System is a low cost, reliable solution for many domestic and industrial applications..

Proceedings of the Peradeniya University Research Sessions, Sri Lanka, Vol. 16, 24th _{November 2011}

32

Evaluation of Widely Used Wireless Technologies for AMI Applications in Smart Grids