observable distribution grid are investigated. A distribution

grid is observable if the state of the grid can be fully determined.

For the simulations, the modified 34-bus IEEE test feeder is used.

The measurements needed for the state estimation are generated

by the ladder iterative technique. Two methods for the state

estimation are analyzed: Weighted Least Squares and Extended

Kalman Filter. Both estimators try to find the most probable

state based on the available measurements. The result is that

the Kalman filter mostly needs less iterations and calculation

time. The disadvantage of the Kalman filter is that it needs some

foreknowlegde about the state.