INTEGRATION OF RECLOSERS INTO SCADA SYSTEMS

Transcription

1 INTEGRATION OF RECLOSERS INTO SCADA SYSTEMS Konstantine Kolevatov, AS Tavrida Electric Export It has become a major task to provide uninterrupted electricity supply to customers and minimize the outage times in the countries of New Europe since adopting the new quality norms of electric services set by the European Union. Thus the success of an electric company and in turn its profitability is directly dependant on the quality of the electricity supplied to the customers. To achieve the highest reliability standards of electrical supply, minimization of outage times and provision for uninterrupted electricity to important customers, many electric companies have begun significantly improving their overhead electricity distribution lines. One of the key products for this improvement is the automatic circuit recloser. In the previous articles we considered the design and distinguishing features of the 27kV reclosers by TAVRIDA ELECTRIC and the most common applications of these devices. Useful operational algorithms of protection and automation functions of the recloser that allow for the resolution of frequent problems occurring on overhead distribution lines were also explained. The aim of this article is to consider possibilities presented by the TAVRIDA ELECTRIC reclosers when used by electric companies in their SCADA systems. TAVRIDA ELECTRIC recloser is outfitted with a fast response drive, i.e. a magnetic actuator that makes it an ideal executive device of a SCADA system. In addition to quick response, the reclosers by TAVRIDA ELECTRIC have built-in systems for remote signaling, control and telemetry that provide for their direct connection into SCADA systems. Implementation of TAVRIDA ELECTRIC reclosers into SCADA systems gives an opportunity to transmit the following information to dispatcher locations in the shortest possible time: 1. Current status of a recloser (on/off). This information is displayed on a dispatcher s monitor in the on-line mode.

2 2. Information about executed trips, pickups as well as operational data on protective equipment and automatic controls. 3. Normal operating parameters of the recloser systems. Monitoring of the systems status will help reduce the possibility of potential failures as well as prevent human injuries caused by electrocution in some cases. It will also reduce the possibility of destruction and theft of electric equipment. For instance, TAVRIDA ELECTRIC recloser is capable of relaying data on battery charge status, unauthorized control cubicle opening or any other troublesome matter. 4. Quality characteristics of supplied electricity in the on-line mode. The recloser by TAVRIDA ELECTRIC can hold up to 3840 such characteristics. For instance, constant monitoring of the supplied electricity frequency, current, voltage and power will prevent the possibility of unacceptable work modes of the interconnected electric equipment, which may cause premature breakdowns.

3 5. Electric Energy Metering and Load Profile. The function of the electric energy metering will allow the personnel of the electric companies to receive information on the modes that the interconnected electric equipment is operating in and provide information on the loads. The recloser by TAVRIDA ELECTRIC records active, reactive and full power in plus and minus directions. Power values are kept in the memory of the recloser and can be relayed to the collection devices at a dispatching location. The function of Load Profile can be used to monitor and optimize the maximum and minimum electric consumption. Electric Energy Metering and Load profile do not require additional expense because these functions come standard with the reclosers by TAVRIDA ELECTRIC.

4 6. Databases of statistics and events with graphic and table views. Accumulated statistics allow evaluating the efficiency of electric company operations, indirectly determine the level of wear and tear of the interconnected electric equipment and expose sections of the electric network needing renovation. Using statistical data various Electric Power Distribution Reliability Indices can be calculated and taken into consideration for developing actions to improve electric company performance. While being able to relay information, the reclosers by TAVRIDA ELECTRIC are also capable of remote control, up/downloading protection and automation settings, en/disabling protection and automation functions as well as selecting one of the four preinstalled independent groups of settings. These features can be beneficial in many cases. For instance, during line maintenance and repairs plenty of time is spent on routine switching required to de-energize the line section where work is being done. It is possible to minimize the outage time by allowing the dispatching personnel to operate switching devices without actually sending a service crew to the installation sites. Another example is seasonal changes of protection and automation settings as this also can be performed remotely via a SCADA system without customers interruption. Besides the above-mentioned features, the experience of creating SCADA systems using the reclosers by TAVRIDA ELECTRIC and their extended functions has exposed the following positive factors arising from their implementation in the electric companies: 1. Reduction of the human factor in occurring faults. Accidental actions of personnel are often the cause of faults and emergency situations. SCADA systems significantly simply the work of the dispatching personnel by reducing the human factor during routine or emergency switching of electrical equipment (the software installed in the recloser doesn t allow a dispatcher to conduct actions contradicting the safety rules), as well as gives a dispatcher the opportunity to see his commands in a mnemonic diagram.

5 2. Display of the entire diagram of the served network zone on a topographic map allows a dispatcher to make more efficient decisions about the actions of the service crew, which reduces the time to eliminate the problem. Dispatching personnel do not always have a clear idea of exactly where electricity distribution lines are located. The topographic map of the terrain displayed on the monitor will allow the dispatchers to have a better idea not only of the installation sites of the switching equipment but also about potentially troublesome and hard to reach sections of the lines. 3. The function of the recloser by TAVRIDA ELECTRIC that records the development of a fault and actions of the protection and automation equipment makes it possible to prevent fault repetition in the future. Every electric supply company has a task to prevent emergency situations. A detailed analysis of fault development and performance of protection and automation equipment can help to achieve this. The reclosers by TAVRIDA ELECTRIC make such data acquisition possible because each recloser comes standard with the function of recording faults and the course of their development. The recloser samples electric parameters 16 times in 20 milliseconds. Average values are calculated by a DSP (digital signal processor) and recorded in the memory. At fault the electric parameters and the protection and automation equipment actions are stored in the memory for the period of the last 1000 milliseconds (of the last 50 cycles of the power frequency) before the trip moment. This will provide the personnel of an electric company with complete and comprehensive information about the fault development and clearance. The recloser by TAVRIDA ELECTRIC can simultaneously hold information on four faults in its memory. The records about fault development and actions of the protection and automation equipment will allow the personnel of an electric company to determine the errors in calculations of the protection settings.

6 4. TAVRIDA ELECTRIC reclosers have wide communication capabilities. In case an electric company already has a SCADA system installed, a question will arise when selecting a supplier to make sure that new equipment can be integrated into the existing SCADA system. Experience in more than 40 counties has shown that the establishment of a new SCADA system using the reclosers by TAVRIDA ELECTRIC or their implementation in the existing SCADA systems is an easy task. Reclosers are programmed with two widely used communications protocols: Modbus and DNP3. Optionally the reclosers can also be equipped with communications protocol converters to support SCADA systems using IEC (103) protocols. In case an electric system uses traditional remote control systems, integration of TAVRIDA ELECTRIC reclosers is also an easy task because the reclosers can have optional modules of discrete programmable inputs/outputs up to 12 inputs and 12 outputs. The same modules can be used in non-standard or limited use SCADA systems. Radio, GSM (GPRS)-modems by various manufacturers, fiber optical communications, direct two-wire or four-wire connection or a trunked communications system can be used to provide connectivity between the reclosers and dispatching locations.

7 The recloser control cubicle has an internal source of 12 V DC. This powers the communications equipment. In spite of its small size, the recloser control cubicle has a section for housing communications equipment that is mounted on the RTU plate. The cubicle has cable glands with variable diameter to connect external cables without breaking the seal. Thus this article explained the possibilities presented by the TAVRIDA ELECTRIC reclosers when used by electric companies in their SCADA systems. You can have more information on the reclosers by TAVRIDA ELECTRIC if you visit TAVRIDA ELECTRIC Export s Internet site at