FOCUS ON SUBSTATION AUTOMATION

The first point, setting the strategic direction, is especially critical as it provides a basis for the cost/benefit calculations and subsequent funding for deployment. In order to formulate a direction in the area of substation automation, it is important to first understand the market requirements and the evolving nature of the marketplace.

Monitoring equipment

Basic Measuring Instruments (BMI) has two new instruments for monitoring power quality, flow and harmonics for three substation feeds simultaneously. The new PQ Nodes have either eight or 16 channels and trigger on both voltage and current disturbances. They work with easy-to-use power evaluation software and offer a digital output for alerting SCADA master stations whenever a disturbance occurs.

They have a high sample date of 256 samples/cycle with high accuracy and a patented sub-cycle analysis technique to capture all voltage and current in addition to calculating watts, volt amperes, wars, power factor energy, and they analyze harmonics up to the 49th for voltage and current.

Siemens Energy & Automation has introduced a control, automation and monitoring system called SICAM that allows utilities to integrate existing substation data with other utility information networks.

According to Siemens, there is an enormous amount of data trapped within conventional substations due to lack of effective access. And, though it is possible to access the data in individual intelligent electronic devices (IEDs) by using proprietary communications software, this approach is not normally designed to fit into a utility's broader information system environment.

SICAM address this problem by providing a coordinated access path into the substation for both the network control system and other information systems which require access to data.

The unit offers a range of substation automation products, or building blocks, which can be use independently or integrated to form a tightly coupled, efficient and secure system, depending on the utility's needs and existing infrastructure. It's based on totally open, distributed architecture that not only allows utility engineers the freedom to select components from a variety of vendors, but enables communications from one component to another via a local area network.

Control and access to substation data SICAM's client/server techniques allow utility operators and engineers to retrieve data and control the substation remotely, using standard information system technologies. Not only does this save traveling time, it provides access to data that allows utility personnel to perform their jobs more efficiently.

This system allows utilities to develop applications that reduce operating and maintenance costs. With appropriate transducers, the utility can develop applications to monitor the condition of equipment over time related to changing operational conditions. This allows condition-based maintenance programs vs. preventative maintenance programs. The system can be programmed to provide immediate warning of the failure of substation equipment and IEDs, such as meters or protective relays. The system can be used to capture load profiles and power quality data from IEDs. This permits tailoring the product or service offering to meet end-customer requirements. Square D Co. offers substation automation tools with its programmable logic controllers that provide redundancy solutions, alternate networking and protocols, and software language programming. Typical used include stand-alone applications to control and monitor capacitor banks, transformer tap changes and reclose circuit breakers. Ideal applications include ring-bus restoration, breaker and one-half control, transfer and sectionalizing.

By integrating the PowerLogic power monitoring system, substation test engineers can remotely monitor and access detailed information about the quality of power being transferred between the substation and the end user.

Integration of substation equipment and IEDs helps utilities cut costs by eliminating unnecessary equipment, reducing transducers, shrinking panel size, cutting the number of vendors, reducing downtime and improving personnel utilization.

Silicon transfer switch

The Power Systems Division of ABB Power of ABB Power T&D Company Inc. has new full integrationed silicon transfer switch (STS). It can transfer power from the primary feeder to a backup feeder in two to four milliseconds, making it one of the fastest switches available.

The STS is an integrated system of thyristors, breakers, aircooling, transfer control, communications and battery backup. It is self-contained with internal diagnostics and monitoring and can be tailored for outdoor pad mounted or indoor metal-clad installations.

The system includes two vacuum breakers and differential protection; dead front construction; operation and source status indicator; redundant switching elements; local and remote communications; continuous power transfer; automatic and manual transfer control and automatic retransfer.

It is currently available for 480 V-35kV systems, 95-125 kV BIL, 600-1,200 A continuous, 10 kA-18kA symmetrical fault current, and any load factor.

Consolidated Electronics Inc.'s monitoring system is designed to take advantage of advances in computer technology. It's abilities include accurate, real-time monitoring of high voltage circuit breakers; eliminating false alarms; predicting future alarms; and providing monitoring and control of selected breaker process and system operations.

The units work on the basic principle of gathering data, storing it and providing calculated information in ways that allow timely, accurate means of making informed decisions as to circuit breaker state. Enhancement options allow control of selected breaker functions, as well as of the breaker itself (trip and lock) when preset alarm levels are reached.

Development of the SM6-1 was a joint effort with the Electric Power Research Institute (EPRI) and beta units installed in the field at various utilities. The SM6-1 has the ability to monitor most functions on an oil or gas breaker and provides a variety of communications and networking capabilities.

The unit is an advancement of the SM6 gas density monitor introduced in 1993. The additional input/output ports of the SM6-1 can considerably upgrade the base unit's capabilities to include a variety of breaker monitoring/control functions.

Enhancement modules are now available to monitor pneumatic and other stored energy systems. Using improved ModBus communications, the SM6-1 can serve as a network controller for other units in the system or as a complete monitoring system for a single breaker. Other intelligent devices can be interfaced to the unit to provide even greater capabilities for monitoring and control.

Western Area Power Authority (WAPA) has successfully used the SM-6 to cut maintenance costs and make an important step in using an IED for automation and monitoring. WAPA uses the trending information to schedule the most critical breakers for maintenance first.

Chelan Public Utility District and paid for its units by reducing false alarms and simplifying inspections. Washington Water Power, Spokane, Wash., uses the monitor for trending and alarm projection information and will be networking SM-6 units using the ModBus protocol.

Transalta uses the system in its northern region where it has been successful in cold -weather applications. It communicates with the units remotely via modem.

BJ Software Systems' RealFlex program is used worldwide to automate alarming, metering and line selection and to monitor breakers, transformers, recloser and IEDs from local and remote locations. The program is scaleable and offers real-time SCADA capability on affordable PC-based hardware.

Redundant network configurations, not standby with automatic fall over and on-line configuration ensure that connections are continuous. The program permits linking substations, field personnel or remote devices to the system via microwave, satellite or modem.

Idaho Power and Baltimore Gas and Electric Co. are among the utilities using the system monitor and provide real-time information to system operators.

Predictive Maintenance

An offshoot of substation automation, predictive maintenance programs are saving utilities millions of dollars. EPRI, Duquesne Light Co., PECO Energy Co. and South Carolina Electric & Gas Co. have developed a substation predictive maintenance (PDM) program that will save these three utilities $23 million over six years.

"Substations are a smaller investment than power plants," acknowledged Project Manager Rich Colsher, "but substation problems can still be costly. A failed transformer, for example, can incur equipment repair and replacement costs, service disruptions, cleanup costs, replacement power costs, even injury to employee."

A reliable predictive maintenance program enable utilities to avoid forced outages-and unneeded maintenance-at the same time.

Most utilities currently perform some predictive maintenance at their substations. "Utilities typically conduct visual inspections, test transformer oil and perform power factor tests," says Bill Vollmer, EPRI engineer with the Monitoring & Diagnostic Center, which helped develop the substation PDM programs. "Some utilities are trying partial discharge detection to identify transformer problems, and some use thermography to look for hot spots." But there is a need for much more organized programs according to Vollmer.

EPRI's substation PDM program offers utilities a comprehensive and organized approach to predictive maintenance. "It helps utilities decide which substation equipment needs testing, what diagnostic techniques to use and how and when to apply them," says George Spencer, the M&D Center's manager of substation project.

The program techniques are all state-of-the-art, including gas-in-oil analysis, partial discharge analysis, ultrasonic analysis, vibration analysis and infrared thermography.

Most of the techniques are real-time, involve portable diagnostic equipment and are conducted on energized substations for maximum effectiveness. The program also emphasizes consistent communications among substation personnel and inspection personnel, detailed data collection and performance trending, and careful documentation of all costs and benefits associated with PDM.