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Example. During the short-circuit testing of two accordingly switch reactors of the type ROST-700 in the course of measurements by ADC of short-circuit inductance there was identified “Chapeau” type distribution.
The value of resulting of measurement root-mean-square deviation comprised: = 0,02693 %; the value of the quantile coefficient t = 1,8143; the confidence interval of a measurement random error comprised Δconf = 0,052 % with the number of measurements of n = 572.
The obtained value Δconf = 0,052 % is lower than stipulated level of error +-0,1 %, which confirms the high accuracy of the determination of short-circuit inductance deviation in the proposed device – Smart Grid Monitoring System [by 1–9, 15–26].
1.9. Conclusion
The most important element of “intellectual of networks” (Smart Grid) are the systems of monitoring the parameters of electrical of equipment.
Smart Grid Monitoring System, which described in this chapter, were proposed to use together with quick-working protection against short-circuit regimes in transformer windings.
At the begi
Smart Grid Monitoring System and co
Short-circuit inductance measurements by ADC there was identified “Chapeau” type distribution of random error.
The determination of confidence interval of measurement random error of short-circuit inductance deviation ΔХs-c by algorithm (1.12–1.26) makes to increase the accuracy of the conducted measurements and the reliability of Smart Grid Monitoring System’s work for the control of short-circuit inductance of power transformers and the reactors.
Smart Grid Monitoring System makes it possible to continuously control the state of power transformer windings without their turning off from the network, to achieve their protection in the case of the appearance of the winding deformations or their damage, and it ensures the high accuracy of the inductance measurement with the confidence interval value of the random error less than +0,1 %. This increases the reliability of operation and the continuity of the power supply of the electrical energy users.
Active Vocabulary of electrotechnical terms and verbs:
Information-measuring system – информационно-измерительная система,
monitoring system – система мониторинга,
Smart Grid – интеллектуальная («умная») сеть,
inductance – индуктивность,
autotransformer – автотрансформатор,
short-circuit – короткое замыкание,
short-circuit testing – испытание на стойкость при коротком замыкании,
accuracy – точность,
accuracy of diagnostic parameters – точность (измерений) диагностических параметров,
confidence interval of measurement – доверительный интервал измерений,
Frequency Response Analysis – (метод) частотного анализа,
transformer winding fault diagnostic – диагностика повреждений обмоток трансформатора,
Low Voltage Impulse method – метод низковольтных импульсов,
short-circuit inductive reactance measurement – измерение индуктивного сопротивления короткого замыкания,
voltage transformer (TV) – трансформатор напряжения,
current transformer (CT) – трансформатор тока;
high-voltage circuit breaker (HVCB) – высокольтный выключатель,
dissolved gas analysis (DGA) – анализ растворённых (в масле) газов,
analog-to-digital converters (ADC) – аналого-цифровой преобразователь,
Short-current Testing Laboratory (STL) – лаборатория (стенд) испытаний на стойкость при коротком замыкании,
to enter- входить,
to include – включать (в себя),
to determine – определять,
to show – показывать,
to prevent – предотвращать.
Exercise 1. Match the English words and word-combinations given below with Russian evuivalents:
equipment a) получать,
application b) появление,
check c) непрерывный,
transformer d) применение,
windings e) оборудование,
Scheme f) среднее (значение),
to decrease g) трансформатор,
continuous h) определение,
measuring i) распределение,
converter j) среднеквадратичное отклонение,
primary k) значимая (величина),
voltage o) проверка,
calculation p) преобразователь,
Average q) случайная ошибка,
root-mean-square deviation r) первичный,
distribution s) схема,
short-circuit regime t) уменьшать,
determination u) напряжение,
appearance v) вычисление (расчёт)
random error x) режим короткого замыкания,
to obtain y) обмотка,
significant z) измеренный,
Exercise 2. Find the antonyms and translate them:
Appearance, increase, scientific, slow digital protection, high-voltage, necessary, automated working place, unscientific, rapid digital protection, nonautomated working place, u
Exercise 3. Study the Active vocabulary. Insert the missing verbs from the list into the sentence and translate them:
The five-year investment program __________ the construction of 73 new substations.
The signal from the control block __________ the protection block (rapid digital protection).
The instantaneous value of inductance is ___________ in the assigned time interval.
The most important elements of “intellectual networks” (Smart Grid) ______ the systems of monitoring the parameters of electrical equipment.
The program allows ________ the average value of the inductance during each period.
Figure 2 _______ the real oscillograms of short-circuit current (Figure 2a), voltage (Figure 2b).
Quick-working protection _______ accidental destruction of the test object and increases the crash safety of the test.
List of verbs: to enter, are, to include, to determine, to show, to prevent, to calculate.
Exercise 4. Answer the following questions to the text.
1. What is the advantage of power transformer monitoring?
2. What is the purpose of digitalization of substations and switchgear of electric power stations, the construction of a digital electrical network?
3. On what principle does the information-measuring system work?
4. Describe the algorithm of the device for continuous monitoring of the state of power transformer windings.
5. What elements and signal converters are included in the block diagram of the device for assessing the state of the windings of power transformers by the value of short-circuit resistance?
6. What are the advantages of the device? Does it provide sufficient speed to process the measured parameters?
7. Why is the value of short-circuit inductive reactance of the transformer reduced to a frequency of 50 Hertz?
8. How are the primary and secondary currents and voltages of the power transformer measured for the further operation of the device?
9. What are the metrological parameters of this device?
Exercise 5. Make а plan of the text and retell the text looking in your plan.
Exercise 6. Discuss the following topics.
1. Smart Grid Monitoring System.
2. Short-circuit inductance measurements.
3. Measurements of short-circuit inductance deviation.
4. Digitization of substations and switchgear of electric power stations, building a digital electrical network.
3. Algorithm of the operation of the information-measuring system for continuous monitoring of the state of the windings of power transformers.
4. Metrological parameters of the device for continuous monitoring of the state of windings of power transformers.