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Rojony Khatun
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Last updated: August 15, 2025

String Efficiency Calculator: Suspension Insulator Analysis

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string efficiency calculator

Calculate string efficiency for suspension insulators by comparing total voltage to disc voltage distribution. Ideal for power transmission line design.

suspension insulator voltage calc

String efficiency identifies the level of uniformity of the juice of suspension insulators. It is given as a percentage where 100 percent means ideal sharing in terms of voltage.

Formula & Table Summary:

l class="list-disc pl-5 text-sm">
  • V_total = Total voltage across string
  • n = Number of discs
  • V_disc_near_conductor = Voltage across disc near conductor
  • electrical insulation efficiency calc

    String Efficiency Calculator calculates the efficiency of a cable of suspension-type insulators, such as those found in high voltage transmission lines. Voltage distribution across discs in a string is never uniform in practice, because of capacitance between discs and because of the tower. The greater efficiency of strings implies the more efficient usage of the units of the insulator, plus the enhanced functioning even when under high voltages. The calculator has applications in electrical engineering in the design of a better transmission line insulator, supplies corona loss reduction, and plots better voltage distribution.

    Corona loss insulator efficiency

    Total Voltage (kV)DiscsDisc Voltage (kV)Efficiency (%)
    13263073.33
    220102878.57

    Frequently Asked Questions - string efficiency calculator:

    What is string efficiency?

    It is the ratio of total voltage to the product of the number of discs and voltage across the disc near the conductor, expressed in %.

    Why is string efficiency less than 100%?

    Due to uneven voltage distribution caused by stray capacitance.

    What is ideal string efficiency?

    100% indicates perfect voltage sharing.

    How can string efficiency be improved?

    By using grading rings, capacitance grading, or longer strings.

    Why is the disc near the conductor most stressed?

    It is directly connected to the line and sees the highest voltage drop.

    What is a typical string efficiency range?

    Usually 70%–90% for HV systems without grading devices.

    Does corona affect string efficiency?

    Yes, corona discharge can worsen uneven voltage distribution.

    What factors affect string efficiency?

    Disc spacing, string length, capacitance, and line voltage.

    Is string efficiency relevant to AC or DC lines?

    Mostly AC transmission lines, but also important in DC HV lines.

    What units are used for string efficiency?

    It is expressed as a percentage (%).

    Rojony Khatun

    Rojony Khatun

    CalculatorToolsProject

    Rojony Khatun is the creator of a free online tools website designed to simplify everyday and engineering-related calculations for students, professionals, and hobbyists. The platform offers a wide variety of basic and advanced calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators, helping users solve problems quickly and accurately.