These advantages are discussed below. Location at one or both ends of line section on the line side in the switching station The main advantage of this location is that the capacitor installation is near the manned sub- stations. These devices are much economical, flexible and energy efficient, but they are responsible for the degradation of power quality by producing harmonic current and consuming excessive reactive power which results in many problems such as resonance, excessive neutral currents, low power factor etc. Most of the loads are inductive, and must be supplied with lagging reactive power. Figure:5 c shows the harmonic distortion in current when non-linear load is connected. Therefore, the addition of capacitors in series with the line, also known as the series compensation, is the best available method to reduce the characteristic impedance of the line, the percentage of series compensation and the optimum location of series compensation will be studied. Advantages of Series Compensation Series compensation has several advantages like it increases transmission capacity, improve system stability, control voltage regulation and ensure proper load division among parallel feeders.
However, it is not very convenient in terms of access for maintenance, monitoring, security, etc. Load Division between Parallel Circuits When a system is to be strengthen by the addition of a new line or when one of the existing circuit is to be adjusted for parallel operation in order to achieve maximum power transfer or minimize losses, series compensation can be used. In order to achieve maximum active power transmission, the reactive power must be compensated. The impedance or reactance of this device is varied in a stepwise manner by controlling the thyristors either in a zero or full conduction operation. Hence, if this power factor has got less valve, the corresponding current I increases for same active power P.
Load this model and save it in your working directory as case1 to allow further modifications to the original system. But disadvantages of passive filter are it results in resonance with the source impedance and it gives fixed compensation. To compensate, a shunt capacitor is connected which draws current leading the source. The system design must limit the voltage to acceptable levels, or the equipment must be rated to withstand the highest voltage that might occur. Traditionally passive filters have been used for mitigation of distortion due to harmonic current in industrial power systems. Frequency Analysis One particular characteristic of series-compensated systems is the existence of subsynchronous modes poles and zeros of the system impedance below the fundamental frequency.
These waveforms are shown here. This will reduce power losses I2R losses in this equipment. Equivalent reactance is varied in stepwise manner. This controller offers no , no transients, and low losses. These divisions make the static capacitor bank more expensive but still the cost is much lower them synchronous condensers. Advantages of Series Compensation 1.
It has a unique ability to perform independent control of real and reactive power flow. Less installation Time The installation time of the series capacitor is smaller 2 years approx. Series Compensation Series Compensation Definition: Series compensation is the method of improving the system voltage by connecting a capacitor in series with the transmission line. In this paper a new method for calculating the maximum power transfer limit of high voltage compensated transmission lines is made. In some case this frequency may interact with weak steam turbine generator shaft and give rise to high torsional stress. The conventional transmission loss estimation methods used by power system utilities in scheduling problems rely on the exactness of the network model.
It also helps in smoothing the current wave shape. The thyristor valve is phase-controlled. In order to minimize the initial surge current in the valve, and the corresponding circuit transient, the thyristor valve should be turned on for bypass only when the capacitor voltage is zero. The signals are picked up by the From blocks in the Data Acquisition subsystem. But series capacitor bank has a major disadvantage. It improves the performance of electrical networks by managing active and reactive power. Moreover, the voltage level of the transmission is an important issue for the selection of the shunt and series capacitor sizes when load voltage dependency is used.
Shunt connected controllers These controllers inject a current into the system at the point of connection. These are referred to as compensators since they compensate for the reactive power in the ac system. Or these could be a unified controllers in which separate series controllers are employed in each line for series reactive power compensation and also to transfer the real power among the lines via proper link. If still further steps are required, the division may be made in the ratio 1 : 2 : 3 or 1 : 2 : 4. During faulty condition, the voltage across the capacitor maybe raised up to 15 times more than its rated value. Three types of load, namely constant power, constant current and constant impedance loads are considered, individually as well as in a mixed combination, and it is shown that the transmission line loss is highest with the constant power load and lowest with the constant impedance load. Since the investigation of this thesis is restricted to compensation at the receiving end of the line, therefore Bus 9 will be assumed to be the receiving-end system.
The fundamental currents of the d-q components are now dc values. After the paper is completely dried and all gases removed from the insulation the capacitor tank is filled with impregnant degassed at the same vacuum. More economical when there are a large no. The reduced value of δ gives higher stability. The cross-section of the conducting parts of the system may also have to be increased for carrying extra ampere burden, which is also not economical in the commercial point of view. However, an extensively huge power system will demand for more compensation schemes and the cost of the line will be enormous In conclusion, the shunt compensation at the load end reduces the problem of over-voltages.