What is distractor efficiency?
The distractor Efficiency (DE) is a component of item analysis that allows the assessor to evaluate the credibility of incorrect options (distractors) of MCQ item. The distractor is considered functioning (FD) if selected by not less than 5% of the group of the examinee (7).
Which relay is used for feeders?
Why is distribution system reliability important?
Reliability is very important issue in dealing with planning and operation of the networks. In distribution system planning, reliability aspects are an important part of the decision base. Thus, to be able to assess and evaluate, reliability is needed in the planning process.
How is Caidi calculated?
- Average Interruption Duration Index (CAIDI)
- erage Interruption Frequency Index (SAIFI)
- B. Customer.
- CAIDI = Σ(ri * Ni ) / Σ( Ni )
- C. System Av.
What are the types of test items?
Five test item types are discussed: multiple choice, true-false, matching, completion, and essay. Information covers the appropriate use of each item type, advantages and disadvantages of each item type, and characteristics of well written items.
Which among these is a part of distribution system?
Answer: A distribution system consists of all the facilities and equipment connecting a transmission system to the customer’s equipment. A typical distribution system can consist of: Substations. Distribution Feeder Circuits.
What is the loss factor in a distribution system?
Distribution loss factors notionally describe the average energy losses for the applicable financial year for electricity transmitted on a distribution network between a distribution network connection point and a transmission network connection point or virtual transmission node.
Which of these systems use the 3 phase 4 wire system?
Secondary system – Use of 3 phase 4 wire system.
How can reliability of power system be improved?
Maintaining Power System Reliability: Three Key Issues
- Design and Installation. Designing electrical systems with operation in mind is crucial.
- Assessments. An assessment of the electrical equipment is key to successfully reducing risk while improving performance and maintaining power system reliability.
- Connected Technology.
What is validity in testing?
The term validity refers to whether or not the test measures what it claims to measure. On a test with high validity the items will be closely linked to the test’s intended focus. If a test has poor validity then it does not measure the job-related content and competencies it ought to.
What is a distractor in multiple choice questions?
Distractors are the incorrect answers in a multiple choice question. Choosing your distractors poorly can make your multiple choice questions much easier or harder than you may have intended.
What is distractor analysis?
An additional analysis that is often reported is the distractor analysis. The distractor analysis provides a measure of how well each of the incorrect options contributes to the quality of a multiple choice item. Once the item analysis information is available, an item review is often conducted.
What is discrimination index and its formula?
The Discrimination Index (D) is computed from equal-sized high and low scoring groups on the test. Subtract the number of successes by the low group on the item from the number of successes by the high group, and divide this difference by the size of a group. The range of this index is +1 to -1.
How is Saifi calculated?
SAIDI/SAIFI SAIDI is measured in units of time, in minutes or hours. SAIFI= (Total No Of customers interrupted)/(Total No. Of Customers served) Assuming all customers connected with the feeder gets interrupted for each feeder failure, SAIFI is measured in units of no of interruptions per customer.
What is reliability index?
Item An… Item reliability is simply the product of the standard deviation of item scores and a correlational discrimination index (Item-Total Correlation Discrimination in the Item Analysis Report). So item reliability reflects how much the item is contributing to total score variance.
What is a test analysis?
Test Analysis in software testing is a process of checking and analysing the test artifacts in order to base the test conditions or test cases. The goal of test analysis is to gather requirements and define test objectives to establish the basis of test conditions. Hence, it is also called Test Basis.
What is the importance of Saifi and Saidi in power system?
SAIFI is the average number of sustained interruptions per consumer during the year. It is the ratio of the annual number of interruptions to the number of consumers. SAIDI is the average duration of interruptions per consumers during the year.
What does Saifi mean?
system average interruption frequency index
Which distribution system is more economical?
Now-a-days, AC system is universally adopted for distribution of electric power as it is simpler and more economical than direct current method. According to scheme of connection, the distribution system may be classified as: Radial system.
What are the steps in item analysis?
Steps in item analysis (relative criteria tests)
- award of a score to each student.
- ranking in order of merit.
- identification of groups: high and low.
- calculation of the difficulty index of a question.
- calculation of the discrimination index of a question.
- critical evaluation of each question enabling a given question to be retained, revised or rejected.
What is item analysis and validation?
To tell how hard the item is. Item Discrimination Index. To tell how well the item to distinguish between high ability and low ability students. After performing the item analysis and revising the items which need revision, the next step is to validate the instrument. Validation-refers to the self itself.
What are the two kinds of item analysis?
- Item Analysis.
- Item Analysis is a process of examining the student’s response to individual item in the test.
- There are two types of item analysis: – Quantitative Item Analysis – Qualitative Item Analysis.
What is the importance of item analysis?
Item Analysis is an important (probably the most important) tool to increase test effectiveness. Each items contribution is analyzed and assessed. To write effective items, it is necessary to examine whether they are measuring the fact, idea, or concept for which they were intended.
What is distribution system reliability?
Reliability of a power distribution system is defined as the ability to deliver uninterrupted service to customer. Distribution system reliability indices can be presented in many ways to reflect the reliability of individual customers, feeders and system oriented indices related to substation.
What is the unit for Saifi?
interruptions per customer
How reliability is measured?
Test-retest reliability measures the consistency of results when you repeat the same test on the same sample at a different point in time. You use it when you are measuring something that you expect to stay constant in your sample.
How do you increase Caidi?
Customer Average Interruption Duration Index (CAIDI) The triangle helps us understand their interaction. Reducing the frequency of outages improves SAIFI. In order to improve SAIFI, more preventative maintenance such as tree trimming and keeping maintenance equipment in tip-top shape should be done.
Why interruption indices are used in distributed power system?
The Utilities commonly use the following reliability indices for frequency and duration to quantify the performance of their systems . (i) System Average Interruption Frequency Index (SAIFI) is designed to give information about the average frequency of sustained interruptions per customer over a predefined area.
Which distribution system is more reliable?
A _________ distribution system is more reliable than the ______ distribution system. Explanation: A parallel distribution system has two end feeding and an alternative of parallel line, so in case there is a fault, the isolator can isolate the faulty part and let the healthy system operate.