In today's era of competition, improving power quality is one of the most important actions utilities can take. It not only differentiates utilities by adding value to their service, but it also avoids possible million-dollar customer lawsuits from service interruptions.

Idaho Power Co. (IPCO), Boise, Idaho, U.S., has come a long way in a short time. Only a few years ago, it was manually recording meter readings for distant agricultural customers on paper charts. Today, the utility remotely monitors the quality of power supplied to hi-tech industrials through state-of-the-art, client-server software linked to digital meters.

To meet high customer expectations concerning price, power quality and reliability, IPCO is installing more distribution automation capabilities to increase efficiency and reduce costs. An infrastructure of digital metering is also being integrated into its existing supervisory control and data acquisition (SCADA) and energy management systems (EMS).

Advanced metering technology was required to adequately measure performance at the customer-utility interfaces. The system consists of a network of meters, computers and software. The meters not only perform traditional revenue metering, but also analyze the power quality and reliability of the delivered product. The metering system can correlate power quality events with their effects and share the information with customers. Many of IPCO's customers have installed advanced metering systems to verify the quality of power they receive and to identify the source of power quality problems.

Integrate Systems IPCO's territory covers about 20,000 sq miles (51,800 sq km), encompassing southern Idaho, eastern Oregon and northern Nevada. But this vast service area _ roughly equal to New Jersey, Rhode Island, Delaware and Maryland combined _ consists of 79 towns and a dispersed population of 700,000. Its 2400-MW summer peak energizes the seasonal irrigation pumps of a large number of far-flung farming enterprises. But IPCO also counts cheese, potato and ore processors among its customers, as well as an increasing number of computer and semiconductor manufacturers. These hi-tech plants _ many running non-stop, power sensitive, computer-controlled processes _ depend on clean, reliable power.

IPCO's 17 hydro and three coal-fired plants supply these diverse customers through 234 substations in a radial distribution system. Distribution is controlled by a SCADA system in which master workstations poll Harris remote terminal units (RTUs).

Use "Box" and Mobile Subs The utility reaches its dispersed customer base through "box" and mobile substations. The tiny agricultural box substations have all necessary equipment encased in low-cost aluminum boxes. About six years ago, digital power meters (3710 ACM) from Power Measurement Ltd. (PML), Victoria, British Columbia, Canada, were installed in these box substations. This installation was a marked improvement over earlier paper charts, which required data to be manually recorded, then converted into digital form and, finally, integrated with other databases.

Once a month, during the growing season when the box stations operate at nameplate capacity, the data accumulated by their meters is transferred onto a laptop PC and brought to the distribution and planning department. The data is analyzed there to prevent the utility from overloading its equipment and risking customer power outages. The data is used in formulating procedures to help irrigators increase the efficiency of their water pumps. Box substations are increasingly metered by the newer PML 3720 ACM digital power meters connected to Harris DART RTUs (Fig. 1).

In addition to box stations, IPCO has mobile substations. The two newest of these _ rated at 40 MVA with on-load tap-changing capabilities _ are ready to roll in an hour as a convoy of three tractor-trailers.

While a mobile is on-line, peak load, equipment temperatures and the mobile's voltage output are measured by a 3720 ACM digital power meter and PML's 3800 RTU, the latter measuring transformer temperatures. Weekly, the data is transferred from the meters' memories to a laptop PC. It is a convenient way to collect date/time-stamped alarm information based on setpoints that have been activated in the meters. If the mobiles are in service longer than two weeks, the meters can be linked to IPCO's central SCADA system through its RS-485 communications or dialup modems.

The new meters are being installed in all newer permanent substations that distribute via secondary feeders. They communicate with the SCADA RTUs over the RS-485 network via PML's Modbus protocol, which provides the communications compati-bility. Since the new meter is programmable, IPCO can choose the information it wants to monitor, including harmonic data.

IPCO diligently seeks to identify harmonic-created problems in its distribution system and to shield its equipment and that of its industrial customers from their disruptive effects. Harmonics can heat the core of substation equipment and potentially create havoc with customers' sensitive, solid-state machines. Also, in the past, industrials generated harmonics that caused problems for IPCO's other customers.

The new meters also eliminate the need for additional transducers to collect voltage, current, watts and VAR information. IPCO no longer has to daisy-chain voltages around different types of transducers, which never gave it the option of getting any harmonic information. The amount of equipment, such as test switches and cables, needed to commission a substation is reduced. Rather than evaluating different equipment types, only one device needs to be tested. The RS-485 allows several meters to be connected together in a substation. The data is now collected directly and more consistently from the remote panel-mounted meters using Modbus.

The meters help IPCO control transformer loads while trending load-cycle data. The utility improves reliability by correcting any problems it finds. The bottom line is that transformers that are not overloaded have a longer life thus avoiding power failures. Information is brought from the meters into the SCADA master stations where specially created screen icons warn of alarm conditions. Collected data can now be sent to several places. For example, information can be sent to the EMS master and to several engineering groups in Boise for analysis. Sharing the same data helps IPCO to quickly correct the cause of alarms. This information also helps the utility project loading conditions in planning future expansion.

Currently, programmable logic controllers (PLC) turn on/off pumps and fans based on inputs from substation transformer pressure and temperature. PLCs also run the tap changers in permanent substations. Beyond metering, IPCO is considering PML's 7700 ION power instrumentation for the control applications. Instead of installing the meter in conjunction with a PLC or similar device, IPCO could do it all with the 7700 ION.

Ethernet and other communications are being added to the 7700 ION, enabling it to be linked to the SCADA system. The result: more channels, greater speed, longer reach and more standardized communications. Ether-net will be used instead of Modbus in substations and also for local area networked engineering group communications.

On-Site PQ Audits Help Customers As presently integrated with the SCADA system, the 3720 ACMs provide a broad range of setpoints that can be triggered on any selected values. IPCO can set the meters to trigger on abnormalities and then analyze that data to determine whether power irregularities were caused by the utility or its customers in their plants.Although not yet connected to the SCADA system, the 7700 ION is being used by IPCO and some of its power-sensitive industrial customers (Fig. 2).

From its newly created power quality department, the utility uses PML's PEGASYS Windows NT-based client/server software to remotely monitor 7700 IONs installed at larger semiconductor manufacturers and food processors. In this analytical/forecasting service, IPCO power quality engineers verify power quality at the customer's interface. This measuring process is trademarked Performance Metering by PML.

As a value-added service, engineers from IPCO's wholly owned subsidiary, Stellar Dynamics (SD), go into these plants to help solve customer power problems. Based on analyses of power system and control processes, SD engineers can design optimum power monitoring for customers and can install the components to form an integrated, industrial control automation system. Once a system is installed and operating, either the customer or IPCO can remotely monitor power quality.

IPCO or SD engineers also determine whether the utility or the customer caused the electrical disturbances. They check for power-related abnormalities affecting larger customers' ability to produce products. But first, they meet the customers, study their process, meter the plants, analyze and model internal power flow and conduct power quality studies.

IPCO has already performed power quality studies on large hi-tech manufacturers, such as Zilog Semiconductors, which has a 7700 ION installed on its premises. These semiconductor companies either have their own dedicated substations or at least a dedicated feeder to isolate them from disturbances caused by the utility's other customers.

Power quality studies are usually triggered by a customer's telephone call or letter indicating concern that its process is not operating at maximum efficiency, possibly costing the company money. This concern applies not only to hi-tech companies but to most large industrials because of the automation built into their facilities. Last year, for example, IPCO responded to a complaint from a cheese factory which, without a doubt, was hi-tech in the cheese-making processes. Inside the warehouse-appearing factory, everything was automated through PLCs and man-machine computer interfaces, operating on shifts, non-stop, 24 hrs/day.

Customers often don't know why PLCs or adjustable-speed drives are coming off-line in their processes. Some hi-tech manufacturers have in-house facilities engineers who, unfortunately, are spread so thin they have to be experts in everything. IPCO can communicate with them more easily because they know what voltage, current and a transient are. But even they get lost when the utility goes deeper into power quality. For this reason, explaining why machines are coming off line is at times difficult. Part of the power quality investigation involves educating ourselves by learning our customers' plant processes. We also must educate the customers that a disturbance may not be caused from right outside their door. It may originate hundreds of miles away, even from another utility.

Once IPCO understands the manufacturer's processes, one of its engineers may meter some parameters to see if starting any motors causes voltage dips, thus possibly crashing the plant's processes. If a utility-supplied disturbance is causing the problems, IPCO will perform a system study to see what disturbances will affect this customer when the utility experiences faults or switching in its power system.

Remote Monitoring of Customers IPCO monitors power-sensitive customers remotely to determine which disturbances affect plant production. From the Boise office PC, PEGASYS continuously pulls data, via dial-up modem over telephone lines, from 7700 IONs at hi-tech manufacturing customers up to hundreds of miles away.

For example, 20 miles (32 km) away in the city of Nampa, Idaho, Zilog Semiconductors has a 7700 ION metering a transformer secondary, the common point affecting two manufacturing buildings. The meter continuously monitors the power system for any disturbance that may affect Zilog's production.

In this case, a disturbance means a variance from an established setpoint. An under-voltage, for example, could be 90% of nominal voltage. Should the voltage fall below that setpoint, the meter takes a high-speed waveform recording of all voltage and current, calls up the Boise computer, and downloads the data that is logged by PEGASYS (Fig. 3).

At work in the morning, IPCO's engineers can immediately see that a disturbance struck because on the PEGASYS' screen the Zilog plant changed color. The number of disturbances that may have happened are also registered on a counter. On screen, the engineers will see graphically displayed information, including recorded disturbance waveforms, current, voltage, min/max values, harmonics and symmetrical components. From this main screen (Fig. 4), engineers can open other windows by mouse clicking _ as in any Microsoft Windows program _ to see more details on the disturbances or any other related data they want to analyze.

The engineers may also check IPCO's transmission outage-reporting system _ running on a SCADA-connected mainframe _ to see if any disturbances occurred on the utility side, such as a fault, trip close or switch. They'll look for any date/time correlation of data between what was downloaded from a customer's meter and what was monitored by the SCADA system. This correlation informs the engineers whether it was a locally caused anomaly or whether it was an internal plant disturbance created by the customer.

Before PEGASYS and the 7700 ION meters, IPCO had no hard data to verify the validity of customer complaints. With the new system IPCO can determine the source of the power disturbance much more effectively.

Service Is Primary Mission IPCO's power quality function goes beyond assigning responsibility for power problems. Its primary mission is service. With deregulation and retail wheeling entering the industry, IPCO is seeing opportunities to service its customers beyond traditional bounds. A customer has already asked IPCO to perform power studies outside its service area. Its industrial customers, headquartered elsewhere, may well have another utility come into their turf to conduct studies. It's becoming quite competitive.

IPCO sees power quality surveys and monitoring as possible revenue generators. It now monitors only its largest consumers, doing what it takes to retain them. However, smaller customers soon could have monitoring equipment installed on their premises by SD and remotely monitored by IPCO. Industrial customers need the ability to determine the magnitude, type, direction and source of disturbances, and they need to correlate any disturbance to other electric distribution system events.

In today's competitive atmosphere, IPCO is aggressively applying state-of-the-art technology to meet customer expectations of the cleanest possible power. This activity not only helps retain present customers but also attracts other companies to move their manufacturing operations to Idaho's attractive business climate and lifestyle. TDW

Don Angell is an engineering supervisor with Idaho Power Co., which he joined in 1981. He has the BSEE degree from University of Idaho. His responsibilities include substation operation and maintenance. He is a member of IEEE.

Kent Venosdel has been an engineer with Idaho Power Co. since 1984. He has the BSEE degree from University of Idaho. His responsibilities include transformer maintenance and operation. He is a member of IEEE. Venosdel is a registered professional engineer in Idaho.

Vernon Padaca is a project engineer with IPCO's subsidiary Stellar Dynamics, which he joined in 1996. He has the BSEE and MSEE degrees from Washington State University and University of Idaho, respectively. His responsibilities include power quality analysis and services, and power system relaying and protection. He is a member of IEEE and is an engineer-in-training in the state of Oregon.