By Carl Goeckeler, KCP&L
Traditional distribution automation (DA) projects have focused on limited remote control operating commands, data acquisition and alarm point monitoring. Kansas City Power & Light (KCP&L) brings added value to its DA system, however, by also changing and managing setpoints, thereby leveraging the power of distributed intelligence within smart field devices.
KCP&L leverages various end devices for capacitor controls, relay protection devices, voltage monitors, load tap changers and others to get full benefits from these intelligent electronic devices (IEDs), including:
- Remote setpoint control that empowers users to push setpoints to their optimal value without deploying field crews to locally augment a setting. (Otherwise users may compromise the setting to a “safe” value.)
- Remote control setpoints for analog input and output that allow KCP&L to avoid central system deployments that can be costly to purchase, develop and maintain.
- Remote setpoint change-commands that allow devices to operate effectively during unique conditions when they would otherwise not operate.
Five KCP&L case studies support this benefit analysis.
Case Study No. 1. Early Capacitor Automation
On August 29, 1991, a thunderstorm moved into the Kansas City, Mo., area, and temperatures dropped from the mid 90s to the low 70s in three hours. Commercial and residential air conditioners continued to run because buildings were still warm inside, but temperature-based controls for capacitor banks switched off because outside temperatures were low. This inappropriate switching came at the worst possible time because KCP&L’s only generating plant in the metropolitan area was off-line. As a result, KCP&L’s transmission and distribution system experienced voltage and VAr flow problems.
A KCP&L distribution automation engineer issues setpoint changes through WinMon to an S&C IntelliCap Plus capacitor control (see case study No. 1).
To ensure this would not happen again, KCP&L executives formed an engineering task force to study the situation. The task force garnered automation strategies and developed a portion of the KCP&L DA vision. The vision included the use of distributed intelligence at the end device along with two-way communication to the IED and the ability to monitor and change IED control setpoints from remote locations.
By using proper remote setpoints with distributed intelligence, the end device operates effectively and automatically even when communication is lost. Thus, the loss of communication (or a central program that drives the status of the remote capacitors) is not the system’s weak link. Operators now monitor the health of the capacitor bank itself, and identify and coordinate proactive capacitor bank repairs prior to peak loading conditions.
KCP&L worked with EnergyLine (since merged with S&C Electric Co.) to co-develop an integrated system that included LiveData server software and the development of WinMon, a powerful graphic user interface that presents data as though the operator were connected directly to the control using setup software in the field.
The first year KCPL used this system, engineers looked at the volt/VAr performance during different times of the day and different days during the four seasons. After a few consecutive seasons of periodically tweaking the control setpoints, engineers could see that the controls truly operated predictably and as desired using this automated process.
Parts or all of this progressive vision and solution have since been shared with the industry and adapted by various suppliers and utilities. WinMon is used in several active large DA projects as a technical cornerstone to help support engineering and operating needs.
Case Study No. 2. ETI Relays and Analog Output Development
KCP&L worked with Telemetric and ETI (Electronic Technology Inc.) from 2005 through 2008 to develop a system that allows remote setpoint monitoring and network protector relay setpoint control. Initially KCP&L used analog inputs to monitor setpoints in the ETI microprocessor network protector relay (MNPR) to ensure KCP&L users configured these important setpoints properly. A Telemetric remote telemetry module (RTM) is connected to each ETI relay. It alarms when the analog input for these critical points move above a pre-set “dead band.” The Telemetric RTM uses commercial cellular communication plus it has a local processor connected to the ETI relay. This functionality further supports distributed intelligence by providing an array of configuration for alarm and communications settings.
Pat Wigley is one of the lead journeymen supporting the network automation project (see case study No. 2).
KCP&L found several instances where an operating anomaly in the field caused certain setpoints in ETI relays to default to factory values. When this occurred, the alarm was noted and reported to the network crews. These KCP&L network crews sent a remote control digital output command to temporarily change the value to a range closer to the desired value. In these cases, however, the crew needed to go to the jobsite and connect to the ETI relay directly with a laptop to restore setpoints to the desired value.
KCP&L journeyman cable splicer Pat Wigley installs a network protector motor that was reported from an alarm from the Telemetric Power Vista Web site (see case study No. 2).
KCP&L co-funded a project with Telemetric to establish analog output to its DNP GPRS RTM device that is used to interface to the ETI MNPR. With this development, users send analog output commands to the control through the GPRS wireless radio. Authorized setpoints can be changed and then read back as DNP analog inputs to ensure successful programming.
KCP&L completed this effort successfully, and a Midwest utility has since adapted this ETI/Telemetric solution and has deployed this application on its sizeable underground network system.
Case Study No. 3. Remote Setpoint Control for Voltage Monitors
KCP&L also uses a voltage monitor (Telemetric TMV-3) that includes a GPRS radio to allow remote configuration of analog setpoint values for voltage alarm levels. This product is installed at a customer’s premise or at select KCP&L system locations to retrieve power quality data. Settings are remotely changed using the Telemetric PowerVista hosted application.
A KCP&L lineman installs a Telemetric TVM-3 on the secondary of a padmount transformer (see case study No. 3).
KCP&L co-developed an application in this device to allow voltage unbalance monitoring between phases. The voltage unbalance threshold percentage and time delay settings are easily changed on the Telemetric Web site. The power quality engineer monitors and controls these setpoints to provide maximum data without being concerned that he may configuring a setpoint value inadvertently that could draw excessive communication bandwidth plus a field trip to reset this point locally.
KCP&L used this product with other automated products that have two-way communications, to resolve a service issue in a rural area. In this case, a rock quarry with large rock crusher motors is served from the end of a long rural distribution feeder. Load balancing is difficult on this circuit because there is a large single- phase distribution lateral near the rock quarry. KCP&L received voltage regulation complaints from the rock quarry, as well as residential customers near it. Resolution of this voltage complaint was particularly challenging because the rock quarry complained of low voltage during motor startup and residential customers also complained of high voltage during times the rock quarry was not operating.
A KCP&L lineman installed a TVM-3 at the rock quarry plus one at a customer’s residence (who reported a voltage complaint). The engineer remotely monitored the data from these two TVM-3s . He reviewed that real-time data along with the rock crusher’s operational data and the operating information that the residential customer logged.
Prior to using TVM-3s, KCP&L would install a service quality recording monitor or more sophisticated power quality meters at the customer premises in a reactive manner. Technicians or engineers made periodic trips to these sites to locally retrieve electronic data from the control. This was done while the technician or engineer waited for additional customer complaints and reports that could be compared, at yet a later date, to the data retrieved from the event recorder.
This new remote control recorder can be easily installed by a lineman. Data is then instantly and simultaneously available to a group of interested parties including the power quality engineer, service center supervisor, system dispatcher, customer account representative and even the customer. This data and use of setpoint control to optimize the data retrieved now enables KCP&L to obtain valuable information to proactively address and resolve service and power quality issues.
Case Study No. 4. Dynamic Voltage Control Using DNP Analog Output
KCP&L further leveraged remote setpoint change applications with its progressive dynamic voltage control (DVC) program. In this case, KCP&L developed remote control features to adjust substation load tap changer setpoints as well as the actual voltage reduction analog percentage values. This led KCP&L the designing and deploying a DVC system.
KCP&L utilizes a mixture of existing and new Telvent remote terminal units (RTUs) to monitor and control 203 substation buses in its metropolitan area. Beckwith 2001C load tap changer controls support DNP and are connected to the Telvent RTU using DNP protocol and serial cable. Special ladder logic is installed in each of the Televent RTUs to restrict load tap changer and voltage reduction settings to an approved range. This KCP&L custom logic also helps ensure that electrical noise on the older two-wire telephone circuits does not accidentally produce any undesired setpoint changes.
KCP&L uses three pre-selected voltage reduction control setpoint ranges at each Beckwith load tap changer control. The customized analog values at each Beckwith control is changed and programmed by remote control. KCP&L personnel then save the analog settings in the Beckwith control and the settings are displayed on the EMS engineering and dispatch screens. After this process is complete, the voltage reduction control function is ready for KCP&L production use for that given substation bus.
The design is unique from many other traditional voltage reduction implementations used at other utilities. Voltage reduction values are truly dynamic and can be uniquely changed and configured for each substation bus “on the fly.” Operating engineers quickly respond to customer voltage complaints by reviewing existing Beckwith load tap changer settings against real time load and voltage data. Analog settings are protected by the KCP&L custom software program in the Telvent RTU that restricts data entry to practical and usable values within a specified analog range and within a defined time window.
KCP&L began deploying the DVC in its metropolitan area late in 2006 and the system was fully deployed by June 2008. The utility believes the use of setpoint control and various technical applications associated with this DVC project make it a unique and cost effective industry model. Voltage is reduced cost effectively without the need for intricate automatic feedback loops between nodes on the circuit and the source. In addition, this deployment of Telvent RTUs further extends and enables the KCP&L two-way DNP communications highway to support future automation projects.
Case Study No. 5. Current Development of Cost Effective Capacitor Monitor/Control
KCP&L changes setpoints through the metropolitan CellNet two-way communications infrastructure using LiveData and WinMon. However, KCP&L also deploys distribution automation in rural applications. The LiveData/WinMon solution depended upon the availability of CellNet (now Landys + Gyr) radio coverage that is not typically present in rural areas.
In 2001, the GPRS coverage was typically restricted to metropolitan areas. Analog communications provided through public carriers was the only option in rural areas. Telemetric provided a bridge solution using the analog public communications carriers’ control channels. KCP&L used this system from 2001 until February 2008 when it generally became obsolete. KCP&L used this temporary radio solution, which gave company personnel experience using commercial carrier communications for distribution automation.
During this period, KCP&L co-developed the Telemetric TC012 capacitor monitor and control. One of the controls more practical features provided users with the option to remotely configure capacitor neutral current alarm thresholds using the analog control channel. This was accomplished by loading a table of analog values into the TC012. Setpoints could be changed between the table values by sending digital output commands. This was a strategic and practical solution.
In the meantime, Telemetric developed applications using GPRS. KCP&L tested GPRS-based products in the metropolitan Kansas City area in 2006 and discovered they were immediately effective. Later in 2006, KCP&L began metropolitan deployment of GPRS RTMs. Initial rural testing showed marginal GPRS coverage. However, commercial carriers have since invested significantly into the GPRS infrastructure that provides expanded and improved rural coverage.
KCP&L and Telemetric are now working to develop an application using GPRS-based analog output and analog input features for the Telemetric TC012. This enables KCP&L a cost-effective way to directly change capacitor control setpoints such as over and under voltage, high and low temperature levels and time delay for each of these. All of these setpoints will be remotely controlled using a hosted application and a secure connection between KCP&L and this hosted application. KCP&L will begin field deployment of this product in the second half of 2009.
Many of the KCP&L distribution automation projects described here are models or templates used by other utilities as they successfully deploy their own projects using similar proven strategies. Remote setpoint change is a progressive and effective distribution automation solution that fits into the smart grid vision for KCP&L and the industry.
Carl R. Goeckeler, P.E., is a consulting engineer at Kansas City Power & Light Co. He can be reached directly at firstname.lastname@example.org.