Improvement of the information-measuring complex for diagnostics of traction power supply objects at high-speed traffic

This paper considers the improvement of the information-measuring complex for diagnostics and monitoring of traction power supply equipment under high-speed traffic, which has several features associated with a multilevel hierarchical structure, spatial distribution of objects, energy modes and functional relationships. The analysis of the transmission and conversion of measuring analogue information into a digital one, considering the maximum frequency of the primary signal spectrum components according to the sampling and quantization parameters to determine the time of the signal converted into a digital form is made. Functional dependencies and an algorithm for measuring information processing, considering the multilevel structure of traction power supply, which allow increasing the reliability and accuracy of diagnosing the main objects in high-speed traffic, are obtained.


Introduction
An integral part of the information-measuring complex (IMC) for diagnosing traction power supply objects in highspeed traffic is it's mathematical, algorithmic and software. Without its development, effective operation of this complex is impossible [1][2][3][4][5][6][7]. Each traction power supply object differs in its design, technological and metrological parameters. In this regard, the methods of diagnostics of these objects differ. IIC diagnosis of traction power supply objects have several features that must be considered in the design, creation and operation of its mathematical, algorithmic and software [3][4][5], namely: (a) Various physical parameters that characterize the mode of operation of interconnected technological objects of substation power equipment and various elements of the contact network with complex structural and functional relationships under load; b) power supply objects have on the one hand a spatial distribution, and on the other hand, have also technological, information and energy interaction of elements, considering the multi-level hierarchical structure, whose input and output parameters must be coordinated structurally, metrologically and with software with the superior devices; c) high speeds cause severe limitations on the duration of information processing in automatic control of motion processes with simultaneous execution of mathematical calculations, data processing programs at given time intervals; The existing system of processing the received measurement information, for example, for installations of the contact network, which is the most vulnerable object, has serious drawbacks, caused by a long interval between visits to their sites by personnel, which leads to a delay in the detection of damage in their work, to the low reliability of data and subjectivity of estimates, and contributes to the development of failure processes. d) The ICP should be improved based on modern microprocessor devices; e) The KIC must be provided with high program stability in the process of diagnostics with the use of joint monitoring methods.

Methods
Improvement of IIC diagnostics and monitoring of the technical condition of traction power supply system equipment in high-speed traffic concerning the above-mentioned features is an urgent task. For diagnostics of substation equipment and installations, the IMS input should receive the output signals of the primary transducers, which are carriers of information on the technical condition of the objects with the numbers ir : yj; ; where N -number of technological objects, for example, contact network supports or number of traction transformer, etc.; a -measured parameter; r -sensor type; n -sensor number. Over the output signals that differ in shape and range of change [y min , y max ] are transformed in the analogue form: their normalization, unification is performed considering steady-state dynamic ranges of output quantities: 0-10 mA, 0-10 V [10]. Considering the fact that the process of modern processing in the PIC for diagnosis and control requires a discrete and digital representation, it is necessary to provide an analogue switch, which should perform two functions: -provide switching of analogue measuring signals coming from primary transducers (current, voltage, phase angles, temperature, electrical insulation resistance, etc.) in independent parallel communication lines via independent parallel communication lines and to one line with the serial transmission of analogue signals via this line. -implement following continuous functions , the sequence of discontinuous or discrete functions , . According to V.A. Kotelnikov's theorem, it is theoretically sufficient to choose the sampling rate equal to; (1) where -is the maximum frequency in the spectrum of the rapidly varying process, considering the Fourier decomposition. However, in diagnostic and control processes, it is reasonable to use the expression [4,5]: (2) where KD is the numerical coefficient. Let us point out here that to increase the reliability in the IC of the diagnosis of traction power supply installations; it is advisable to use the cyclic mode of interrogation of the primary transducers. In this case, the cycle time Tir for processing devices can be found as: , where n is the number of sensors (transducers) connected to the processing device. The sampling frequency of the output signals for the primary transducers of the processing devices is found in the form: , (4) where -is the sampling frequency determined by (2); n is the number of primary transducers. With (2) and (3) we obtain: The discrete representation of the measured value must then be converted into a digital form. It is known [5] that the value of the analogue signal is performed according to the duration of the corresponding duration of the analogue-to-digital conversion. The error value is determined by the duration of conversion. Duration of conversion at which the increment of a primary signal with a set rate of change does not exceed a step of quantization. Considering the highest rates of change of measured physical quantities of objects in high-speed motion, to estimate the duration of the transformation it is possible to use the following formula [3,4]: (6) where h-number of quantization levels of the analogue-to-digital converter; -is the maximum frequency of the controlled process.

Results and Discussions
Following the above, a multilevel functional block diagram of the IIC diagnostic and control of traction power supply is shown in Fig. 1. The proposed multistage IMS (Figure 1) is designed for technical control, diagnostics and monitoring and consists of three stages. The first stage of the IMS includes the equipment installed mainly on the poles and mounted in the equipment of the traction substation (TS) and overhead system (OS). The second stage of the IIC consists of data collection points, automated monitoring and control systems (AMCS), an automated system for diagnostics and monitoring of traction transformers and contact network installations, as well as tile mechanics, communication and SCADA systems. The third stage of the IIC includes a system of operational and dispatch control, an automated control system of industrial and economic activities, as well as the means and system of data transfer to the management of "Uzbekistan Temir Yullari". Primary processing (PA) of the measured data is carried out in real-time using methods of increasing the reliability, in the simplest way of multiple repetitions of messages and using microprocessor modules following the parameters of the diagnostic and controllable values applied [4]. From the software device, the flow of digital counts ... goes to the input of the digital processing device (DPC), built on composite microprocessor modules. Here -sampling cycle (period) time for incoming information messages; T -period of digital readout streams, Tmin -minimum permissible value. In this case, it is necessary to specify that the rate of primary processing of information should correspond to the sampling period .
Let us consider methods and algorithms for the calculation of numerical characteristics in the statistical processing of measurement information by traction power supply IMS processors. In real conditions, production, technological, electrodynamics disturbances, introduced by sensors and by the test instrument itself, affect the measurement results or contain a certain uncertainty.  [8].
Consider the technical condition and diagnosis of traction transformers (CTs) installed on the section of high-speed traffic with numbers ir, Let us also give a list of measured parameters with numbers j, In a considered IMS after discretization and quantization, a stream of measurement results in the form of a sequence of digital messages is formed. Then a cyclic interrogation with time interval Tmin=Tir=∆t is performed. Each measured value j is repeated three times, numbered from 1 to . To simplify further descriptions, we omit the indices i and r. Then we obtain the series yj1, yj2, ..., yjζ , i.e. the series yiq, q -is the number of measurements of parameter j at the time interval τ. In practice, the measured process yjq is random.
Consider the methodology of determining the diagnostic parameters and technical condition of CTs of traction substation, implemented by IIC, which makes measurements of the determinants of the following quantities: UAB , UBCinput and output voltages of CT, V; I1, I2currents at the input and output of CT, kA; t is the temperature of the output winding; P1 and P2 are the active powers at the input and output of the CT. The reverse-sequence current, the magnitude and initial phase of which are determined by the expressions [3] are determined: Insulation resistance of CT winding inputs, condition of magnetic wire, R60/R15 absorption coefficient, the electrical load acting on the temperature of CT upper oil layers tnom=35-390C and decrease of R60/R15 ratio, up to 1,3 Mohm, are the determinants for decision making about CT operation. Voltages of 3, 5, 7 harmonics are usually equal relative to the first harmonic U5=6,7%; U3=5,8%; and U7=4,9%. The overheating of CT windings and magnetic core is significantly affected by the increased reactive power Q and the presence of higher harmonics in the power supply system, caused by the inductive nature and asymmetry of the traction load. The main factor in assessing the technical condition is also the value of the electrical load, determined by the weight and frequency of passing trains [10]. To describe and analyze the functional dependencies, it is assumed that one-dimensional random processes jq y , , where  is the number of voltage measurements j u on the interval  ?
We will take the dispersion j u as the dispersion in the form: The proposed algorithm for interrogating sensors and secondary transducers installed on the overhead system is shown in Fig. 2 Consider the proposed algorithm for interrogating signals to carry out diagnosis and monitoring of a particular section of the contact system and detection of emerging changes in its elements in a continuous automated mode. The parameters to be diagnosed are: tension force and temperature of contact wires and carrying cables, movement of compensating device weights, inclination angles, values of pushing back on contact wire [9]. Each sensor is connected by a wire link to the nearby hub of the information gathering and transmission unit, which has a microprocessor device for primary analogue-digital processing. Based on the developed mathematical dependencies and algorithms, the software of the information and control system for diagnostics and monitoring of traction power supply objects, which provides automation of measurement processes, collection, transmission, processing of information in real-time, was implemented.

Conclusions
The efficiency of the traction power supply system in high-speed traffic depends on the level of integration and quality measurement in the information-measuring complex for diagnosing and the process of monitoring the technical condition of electrical equipment. The proposed IMS is a set of components of measuring tools, mathematical, algorithmic and software and decision making at all levels of traction power supply system management in high-speed railroad traffic.