English Original Reader for Technical Students. Power transformers: short-circuit testing, monitoring systems (Smart Grid) - страница 6

This “imposition” of measurement confidence interval is inadmissible, since in certain cases this hampers the estimation of winding condition state of transformer: if this deviation ΔХs-c insignificantly, i.e. it is connected with a measurement error, then of changes in the windings does not occur; but if it significantly, i.e. it corresponds to the development of residual deformations in the windings, then it must be considered for evaluating the winding condition state in order not to bring it to the destruction [5–14].

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:

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].

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 beginning of winding deformations, and also in the case of winding turn-to-turn internal short-circuit the value of inductance L is developed to increase, or to decrease.

Smart Grid Monitoring System and connected with it protection block were stopped the process of winding destruction.

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.

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,