Transformer equipment is one of the key elements of any power system that affects its reliability.
Due to continuous severization of the requirements pursuant to stability, safety and efficiency of modern power systems’ operation, on-line intelligent systems for monitoring of operating modes and condition assessment of electrical equipment installed at power grids are becoming more and more popular.
In up-to-date conditions of automation of power systems and power grids, implementation of automated control systems, the terms "intelligent grid" and "intelligent transformer" are increasingly found.
Intelligent Transformers mean transformers and autotransformers which include special electronic monitoring and control devices ensuring the following functions:
- Electrical energy quality registration and analysis at all voltage sides (high, intermediate, low) in steady state processes.
- Fault and healthy transient processes registration and analysis, including: commutations (switching on, switching off) and shot circuit regimes.
- Monitoring of electrical, thermal and mechanical parameters of the main units of the transformer construction with expert estimation of the equipment technical condition and loading capability and service life.
- Remote automatic optimum control of cooling system
- Remote automatic optimum control of tap changers
Above mentioned functions are realized in Monitoring, Diagnostic and Control Expert System by PJSC «Zaporozhtransformator» (PJSC ZTR).
Functions of Monitoring System
Monitoring, Diagnostic and Control Expert System ESMDU-TRANS is purposed for:
- technical condition control of the transformer equipment within operation
- generation of diagnostic, warning and emergency messages
- database maintenance
- communication of information related to technical condition of the equipment to automatic control system of substation (ACS SS)
Substation maintenance staff and experts of transformers are the users of system.
Hardware structure of ESMDU-TRANS
Hardware structure of ESMDU-TRANS has three – level system:
Level 1 – sensors and sensing transmitters. At this level, conversion of measured physical parameters into unitized signals is realized for measured data transfer to level 2.
Level 2 – controllers and input/output devices. At this level, signal processing from level 1, performance of calculations of series of diagnostic parameters and generation of digital bitstream is realized for data transfer to level 3. Constructive arrangement is inside the diagnostics cabinet.
Level 3 – server of data acquisition and expert evaluation. At this level, acquisition and processing of digital bitstreams, archive maintenance, implementation of expert evaluations, information display on monitor screen and informational communication with adjacent systems of higher level is realized. Constructive arrangement is inside the Workstation cabinet.
Software (SW) and database (DB) structure
Software of ESMDU-TRANS system has four-level structure:
Level 1 – software of intelligent measuring instruments:
- Instrument for bushing insulation quality control;
- Instrument for moisture- and gas-content in oil;
- Fiber optic sensors monitor.
Level 2 - software of controllers of connection cabinet and diagnostics cabinet, which ensures:
- Continuous data reading of all analog, digital and relay signals and instruments with different sample rate (from 1 time per 30 minutes up to 7MHz)
- Data pre-processing and storage, data exchange with software of level 3;
- Formation and generation of signals for transformer relay protection;
- Formation and generation of control signals by cooling system devices (pumps, fans, valves);
Level 3 – software of Workstation industrial computer, ensuring:
- Continuous reading (with 3 seconds resolution) of measurement data transferred by diagnostics cabinet controller, primary analysis and recording of this information in actual database (if required);
- Periodical (as initiated by user) input to the system referral database of information related to diagnostics results of transformer oil physical and chemical parameters, and results of dissolved gas-in oil chromatographic analyses, carried out on the grounds of research of oil samples in specialized laboratories;
- Continuous calculation of electric power diagnostics parameters according to real steady-state and transient modes of transformer operation based on given data, recording of this information in actual database;
- Continuous calculation of diagnostics parameters related to technical condition of the transformer functional subsystems based on reference data and measurement data, recording of this information in actual database (if required);
- Continuous expert evaluation of diagnostics parameter current values of electric power and all transformer functional subsystems;
- Formation of conclusion as for degree of risk to continue normal operation of individual subsystems and the transformer as a whole;
- Visualization of information for Workstation user as referred to measured and calculated values of diagnostics parameters and results of expertises performed for transformer technical condition evaluation.
Level 4 – software of WEB server or local computer network, ensuring simultaneous visualization of information for several Workstations’ users as referred to measured and calculated values of diagnostics parameters and results of expertises performed for transformer technical condition evaluation.
System user interface
The user interface is grouped into virtual devices corresponding to the various hardware subsystems.
There are virtual devices to navigate the system, to visualize the information for the user, to build reports, to make reference.
Virtual device “System superintendent (operator) panel” is specified for visualization of the expertise work results of all virtual devices. Buttons in the left side pointing technical condition of the subsystems for all phases of transformer. Those buttons are designed for calling additional panels and corresponding virtual devices. Diagram with list of expertise with a help of color defines results of the work of each expertise. Messages of the expertise results are defined in right upper part of the device in online system messages recorder. Most dangerous (fault) signal conditions are viewed by color of indicators in right lower part of the device.
Virtual device “Electrical energy parameters (steady state processes)” is designed for electrical power parameters of the network in steady state. At this state parameters of measured instantaneous current and voltage values of all phases (A, B, C) and sides (LV, IV, HV) are analyzed. The following is calculated using this measured values : instantaneous and real values of linear and phase powers, parameters that characterize network energy quality and non symmetry of phase signals, overvoltage statistics, harmonic compounds of the all steady state signals (amplitudes, phases).
Similar virtual devices are designed for all functional subsystems of equipment, including:
- electrical power parameters control in steady state
- electrical power parameters control in transient processes
- signal control of technological protection devices
- electromagnetic and thermal parameters control of the magnetic system
- electromagnetic and thermal parameters control of the windings
- solid isolation and transformer oil diagnostic parameters control
- bushings diagnostic parameters control
- diagnostic parameters and regimes control of cooling system work
- tap changer diagnostic parameters control.
PJSC ZTR experience in delivery of monitoring systems
ZTR has more than 10 years experience of Monitoring system deliveries together with transformer equipment. In doing so, all projects of Monitoring systems, choose and installation of sensors, development of cooling system and tap-changer control cabinets, designing of diagnostics algorithms and expertise of diagnostics parameters at Workstation has been performed by “ZTR” PJSC. However, hardware and software for data acquisition and data transfer to Workstation has been executed by co-executors.
- 2001 - delivery of the first monitoring system.
- 2008 - number of Monitoring system deliveries reached 50.
- 2011 – the 100-th delivery of Monitoring system.
- 2013 - more than 150 deliveries of Monitoring systems.
- In 2011 on the grounds of previous experience the first version of the ESMDU-TRANS system was developed and implemented in trial operation by “ZTR” PJSC based on Compact Rio controllers and LabView software designed by National Instrument (NI).
- In 2012 the additional software for user training was developed.
- In 2013 ESMDU-TRANS successfully passed mechanical, climatic and electromagnetic compatibility tests in the laboratories of GOSSTANDARD of Ukraine and obtained proper reports. System version updated according to test results was implemented for TNC-1 000 000/500 and TRDNS-63 000/35 transformers for TPP Berezovskaya, ATDCTN-125000/330/110 (2 pcs.) for Ruchej s/s, AODTN-83333/500/150 (4 pcs.), ODTN-83333/500/150 (4 pcs.) (Uruguay).
- Since 2011 up to 2013 ESMDU-TRANS was tested with more than 20 transformers at ZTR testing fields during routine tests.
Diagnostic cabinet with controller of actual time installed near the transformer.
Cabinet of computer workstation installed at premises of substation.
|Inputs and outputs
AC transmission channels: 0-1 А, 0-5 А
DC transmission channels: 4-20 mA
Transmission channels of AC voltage: 0-100 V
RTD inputs: Pt-100
Transmission channels of relay signals: dry contact
Number of transmission channels is determined by type of controlling device and requirements of the Customer.
Nonvolatile memory of controller is used for keeping information of emergency events.
SQL database is used for keeping of long-term data, archiving of alarms and events.
Appendix installed in PC.
Web-server for data browsing at the remote working place
|RS-232, Ethernet 10/100, fiber optic element
|IEC 61850, IEC 60870, Modbus, OPC
Material: stainless steel
Protection degree: IP54
installation: close to the transformer on the separate foundation
|Cabinet of workstation
Material: stainless steel
Protection degree: IP54
Installation: indoors of substation
|-40 up to +60°C
|Electromagnetic compatibility: IEC 61000, GOST 32137-2013