Qv Face

voltage drop problem has been one of the major problems faced by electric utilities in many countries. The problem is also a major concern in the electricity system and planning. It can be characterized by a continuous decrease of the system voltage. In the initial phase of decreased blood system begins gradually and then decreases rapidly. Power stressed system, namely the loading of high power active in the system. In bulk transmission system to avoid the cost of building new lines and production facilities. When a network of bulk is operated near the limit of the voltage instability, it becomes difficult to control the reactive power margin for this system. Therefore, system stability becomes a major problem, and should appropriately be found to monitor the system and prevent the collapse of the system. One of the main reasons for the collapse voltage is the burden of the electricity system, which consists of long transmission lines. The system seems unable to meet the demand of reactive power. Produce the requested reactive power in synchronous generators, synchronous condensers or capacitors may exceed the electrostatic problem [1]. Another solution is to build transmission lines to the lowest nodes. voltage drop can occur because of a major disruption in the system such as failure or breakdown of generating lines.

In many algorithms have been proposed in the literature for the analysis of voltage stability. Most utilities have a tendency

depend regularly on conventional load flow for such analysis. Some of the proposed methods are concerned with the analysis under the voltage instability of small perturbations in the parameters of the system load.

II. Flow problem POWER

The power flow solution predicts that the state's electrical network will be when it is subjected to a specified loading condition. The result of the flow of power is the voltage magnitude and angle at each node of the system. The bus voltage magnitudes and angles are defined as state variables of the system [2]. This is because they allow all other system quantities must be calculated such that the flow of active power and reactive power, voltage drops, power losses, etc., the solution of power flow is closely associated with the analysis of voltage stability. It is an essential tool for the assessment of voltage stability. Most research on voltage stability deals with the method of calculation of power flow. The problem of power flow solves the complex matrix equation

(1)

(2)

The Newton-Raphson algorithm is the most general and reliable way to solve the problem of power flow. It is based on successive iterations of the linearization using the first term of Taylor expansion of the equation to solve. According to equation (1), we can write the equation for node k (k bus)

(3)

(4)

(5)

, (6)

(7)

= (8)

.