A balanced three-phase load of 10 MVA, 80 percent power factor, and 33 kV is connected at the end of a transmission line whose line impedance is 1.2 + j5 ohms per conductor. Determine the percent regulation of the line. A. 3.25% B. 3.03% C. 3.80% D. 3 (2024)

`); let searchUrl = `/search/`; history.forEach((elem) => { prevsearch.find('#prevsearch-options').append(`

${elem}

`); }); } $('#search-pretype-options').empty(); $('#search-pretype-options').append(prevsearch); let prevbooks = $(false); [ {title:"Recently Opened Textbooks", books:previous_books}, {title:"Recommended Textbooks", books:recommended_books} ].forEach((book_segment) => { if (Array.isArray(book_segment.books) && book_segment.books.length>0 && nsegments<2) { nsegments+=1; prevbooks = $(`

  • ${book_segment.title}
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Make an ajax call to the server and get the search database. let databaseUrl = `/search/whiletype_database/`; let resp = single_whiletyping_ajax_promise; if (resp === null) { whiletyping_database_initial_burst = whiletyping_database_initial_burst + 1; single_whiletyping_ajax_promise = resp = new Promise((resolve, reject) => { $.ajax({ url: databaseUrl, type: 'POST', data:{csrfmiddlewaretoken: "ef7hMNfs7tZJV6z8ZBcJVJSw0c9QFLGphXvf1mgHjFnfrWQONvDPj6gEHT3OkKbV"}, success: function (data) { // 3. verify that the elements of the database exist and are arrays if ( ('books' in data) && ('curriculum' in data) && ('topics' in data) && Array.isArray(data.books) && Array.isArray(data.curriculum) && Array.isArray(data.topics)) { localforage.setItem('whiletyping_last_success', (new Date()).getTime()); localforage.setItem('whiletyping_database', data); resolve(data); } }, error: function (error) { console.log(error); resolve(null); }, complete: function (data) { single_whiletyping_ajax_promise = null; } }) }); } return resp; } return Promise.resolve(null); }).catch(function(err) { console.log(err); return Promise.resolve(null); }); } function get_whiletyping_search_object() { // gets the fuse objects that will be in charge of the search if (whiletyping_search_object){ return Promise.resolve(whiletyping_search_object); } database_promise = localforage.getItem('whiletyping_database').then(function(database) { return localforage.getItem('whiletyping_last_success').then(function(last_success) { if (database==null || (new Date()) - (new Date(last_success)) > 1000*60*60*24*30 || (new Date('2023-04-25T00:00:00')) - (new Date(last_success)) > 0) { // New database update return get_whiletyping_database().then(function(new_database) { if (new_database) { database = new_database; } return database; }); } else { return Promise.resolve(database); } }); }); return database_promise.then(function(database) { if (database) { const options = { isCaseSensitive: false, includeScore: true, shouldSort: true, // includeMatches: false, // findAllMatches: false, // minMatchCharLength: 1, // location: 0, threshold: 0.2, // distance: 100, // useExtendedSearch: false, ignoreLocation: true, // ignoreFieldNorm: false, // fieldNormWeight: 1, keys: [ "title" ] }; let curriculum_index={}; let topics_index={}; database.curriculum.forEach(c => curriculum_index[c.id]=c); database.topics.forEach(t => topics_index[t.id]=t); for (j=0; j

    Solutions
  • Textbooks
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  • Solutions ${viewAllHTML}
  • `); let questionUrl = "/questions/xxx/"; let askUrl = "/ask/question/xxx/"; solution_search_result.forEach((elem) => { let url = ('course' in elem)?askUrl:questionUrl; let solution_type = ('course' in elem)?'ask':'question'; let subtitle = ('course' in elem)?(elem.course??""):(elem.book ?? "")+"    "+(elem.chapter?"Chapter "+elem.chapter:""); solutions_section.find('#whiletyping-solutions').append(` ${elem.text} ${subtitle} `); }); $('#search-solution-options').empty(); if (Array.isArray(solution_search_result) && solution_search_result.length>0){ $('#search-solution-options').append(solutions_section); } MathJax.typesetPromise([document.getElementById('search-solution-options')]); } } function build_textbooks() { $('#search-pretype-options').empty(); $('#search-pretype-options').append($('#search-solution-options').html()); if (Array.isArray(textbook_search_result)) { var books_section = $(`
  • Textbooks View All
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    A balanced three-phase load of 10 MVA, 80 percent power factor, and 33 kV is connected at the end of a transmission line whose line impedance is 1.2 + j5 ohms per conductor. Determine the percent regulation of the line. 
A. 3.25% 
B. 3.03% 
C. 3.80% 
D. 3 (2024)

    FAQs

    What is the power factor of each phase for a 3 phase unbalanced load? ›

    A three-phase unbalanced load is constituted by two equal linear inductive impedances in phases “a” and “b” with a power factor √2/2, and a capacitive linear impedance in the phase “c” with a power factor of same value but active power consumption doubled.

    What is the expression of power factor taken by 3 phase load? ›

    The formula for power of a 3-phase circuit is Power = Voltage (V) x Current (I) x Power Factor (PF) x square root of three. If we assume the load on the circuit is resistive only, power factor is unity (or one) which reduces the formula to P = V x I x square root of three.

    What is the formula for 3-phase load balancing? ›

    For 3-phase systems, we use the following equation: kW = (V × I × PF × 1.732) ÷ 1,000. Again, assuming unity PF and solving this equation for “I,” you get: I = 1,000kW ÷ 1.732V.

    How to calculate power factor in 3-phase? ›

    Now, let's see how we can calculate power factor in a three-phase circuit:
    1. Measure the voltage (V) across the load.
    2. Measure the current (I) through the load.
    3. Determine the real power (P) in watts.
    4. Calculate the apparent power (S) using the formula: S = √3 * V * I.
    5. Calculate the power factor using the formula: PF = P / S.

    How do you calculate 3-phase load? ›

    For calculating full load current in a 3 phase system we have to use the formula W =root 3 ×VL ×IL ×cos teeta (power factor )now IL =W /1 . 732 ×VL ×P.f . Here in this formula W = power, root 3 =1.732, VL =Line voltage, IL =Line current and cos teeta= power factor.

    What is the power factor of a 3-phase induction motor at load? ›

    The power factor of induction motors varies with load, typically from around 0.85 or 0.90 at full load to as low as about 0.20 at no-load. At no load, an induction motor draws a large magnetizing current and a small active component to meet the no-load losses.

    What happens if loads are unbalanced in 3-phase? ›

    Unbalance or imbalance is a measurement of the inequality of the phase voltages. Voltage imbalance is the measure of voltage differences between the phases of a three-phase system. It degrades the performance and shortens the life of three-phase motors. The impact of the transients on motors can be severe.

    How do you calculate the power factor of a 3-phase circuit? ›

    Now, let's see how we can calculate power factor in a three-phase circuit:
    1. Measure the voltage (V) across the load.
    2. Measure the current (I) through the load.
    3. Determine the real power (P) in watts.
    4. Calculate the apparent power (S) using the formula: S = √3 * V * I.
    5. Calculate the power factor using the formula: PF = P / S.

    What is a three-phase voltage unbalance factor? ›

    Voltage unbalance is a condition in which the three-phase voltages differ in amplitude or are displaced from their normal 120° phase relationship, or both. The degree of unbalance is usually defined by the ratio of the negative sequence voltage component (see Chapter 28) to the positive sequence component.

    What is the method of power measurement for a 3-phase 3 wire unbalanced load? ›

    The two wattmeter method is used for measuring the power in three-phase, three-wire systems. It is applicable to both balanced and unbalanced loads and can be used in star (Y) or delta (Δ) connected systems.

    References

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