On a power network, events are desired to be monitored to discover their reasons and to take preventive actions. Today, phase measurement units are used to obtain transient data of network, however these devices are expensive and it is not considered as a practical option to place one on each node of the network. Therefore, methods of estimating voltages and currents at non-measured points of the network are required. In this study, a special first-order Kalman Filter is introduced and transients on a power network connected by short lines are estimated using only line parameters. Simulation results show that the method gives satisfactory prediction results despite noisy measurements.