Ֆերանտի էֆեկտը փոխմիացման գծերում. Ինչպիսին է այն.
Ինչ է Ֆերանտի էֆեկտը?
Ֆերանտի էֆեկտը երևույթն է, որը նկարագրում է լայն հղումներով շարժման գծում ստացող կողմի սպառող լարման բարձրացումը առաջ ուղղվող լարման նկատմամբ: Ֆերանտի էֆեկտը ավելի շատ դիմակայելի է, երբ բեռը շատ փոքր է կամ կապված չէ (այսինքն, բաց շղթա): Ֆերանտի էֆեկտը կարող է նշվել գործակցով կամ տոկոսային բարձրացմամբ:
Համարժեք պրակտիկայում մենք գիտենք, որ բոլոր էլեկտրական համակարգերի համար հոսանքը հոսում է բարձր պոտենցիալից 낮은 전위로 이동하여 시스템 내의 전기 잠재차를 보상합니다. 모든 실제 사례에서, 송전 단말 전압은 선 손실 때문에 수신 단말 전압보다 높으므로, 전류는 소스 또는 공급 단말에서 부하로 흐릅니다.
Բայց Սիր Ս.Զ. Ֆերանտին 1890 թվականին մի աստounding theory about medium transmission line or long-distance transmission lines suggesting that in case of light loading or no-load operation of the transmission system, the receiving end voltage often increases beyond the sending end voltage, leading to a phenomenon known as Ferranti effect in a power system.
Առաջացող գծում Ֆերանտի էֆեկտը
.getLong transmission line can be considered to compose a considerably high amount of capacitance and inductance distributed across the entire length of the line. Ferranti Effect occurs when current drawn by the distributed capacitance of the line itself is greater than the current associated with the load at the receiving end of the line(during light or no load).
This capacitor charging current leads to a voltage drop across the line inductor of the transmission system which is in phase with the sending end voltages. This voltage drop keeps on increasing additively as we move towards the load end of the line and subsequently, the receiving end voltage tends to get larger than applied voltage leading to the phenomena called Ferranti effect in power system. We illustrate that with the help of a phasor diagram below.
Thus both the capacitance and inductor effect of transmission line are equally responsible for this particular phenomena to occur, and hence Ferranti effect is negligible in case of a short transmission line as the inductor of such a line is practically considered to be nearing zero. In general for a 300 Km line operating at a frequency of 50 Hz, the no-load receiving end voltage has been found to be 5% higher than the sending end voltage.
Now for the analysis of the Ferranti effect let us consider the phasor diagrams shown above.
Here, Vr is considered to be the reference phasor, represented by OA.
This is represented by the phasor OC.
Now in case of a “long transmission line,” it has been practically observed that the line electrical resistance is negligibly small compared to the line reactance. Hence we can assume the length of the phasor Ic R = 0; we can consider the rise in the voltage is only due to OA – OC = reactive drop in the line.
Now if we consider c0 and L0 are the values of capacitance and inductor per km of the transmission line, where l is the length of the line.
Since, in case of a long transmission line, the capacitance is distributed throughout its length, the average current flowing is,
Thus the rise in voltage due to line inductor is given by,
From the above equation it is absolutely evident, that the rise in voltage at the receiving end is directly proportional to the square of the line length, and hence in case of a long transmission line it keeps increasing with length, and even goes beyond the applied sending end voltage at times, leading to the phenomena called Ferranti effect. If you’d like to be quizzed on the Ferranti effect and related power system topics, check out our power system MCQ (Multiple Choice Questions).
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