By Carl Goeckeler, KCP&L
Kansas City Power & Light (KCP&L) has aggressively developed and deployed new distribution automation (DA) technologies over the years. Ten years ago, the utility began exploring DA options for rural areas beyond the existing SCADA system’s reach. Cost and time constraints on an already overtaxed KCP&L real-time systems group precipitated a look at a wireless DA system from Telemetric (now Sensus).
|Tianling Wu, KCP&L senior asset management engineer, retrieves reports used to develop and deploy installation inventory and track essential maintenance for KCP&L’s capacitor automation installations.|
The system uses cellular radios to remotely monitor and control reclosers, capacitor banks, switch controls, faulted circuit indicators, voltage regulators and voltage monitoring devices on system circuits using industry standard DNP 3.0/IEEE 1815 protocol. The DA system can transmit via digital GSM/GPRS or CDMA/1X radios or private spectrum networks. It is built on a Web-based architecture that offers a hosted service, setting it apart from the competition. KCP&L uses Sensus’ PowerVista Web-based application as a key element in DA implementations.
A hosted service for critical infrastructure such as an electric distribution system might cause some power engineers to hesitate, but the benefits are considerable. Additional IT hardware isn’t necessary and maintenance-hosted applications can be implemented faster with less risk to existing systems. In addition, security was addressed with robust architecture, policies and procedures. The system uses an early version of what is now known as cloud computing.
This Internet-based, hosted application enables real-time access to distributed assets with any Web-enabled personal computer (PC) or wireless device through a secure account with the latest cybersecurity technology. Systems are routinely backed up and offer redundancy through multiple servers.
KCP&L’s hosted DA system has undergone considerable development. Initial deployments used analog cellular communications. The analog cellular network had limited data capacity and primarily communicated with capacitor controls. Functions were equally limited on the Telemetric system. KCP&L saw potential in the unique remote telemetry module (RTM) and capacitor control–enough that KCP&L became a co-developer with Telemetric to refine the system. In addition, a transition from analog to digital cellular by 2007 greatly increased coverage and capacity, while improving latency.
KCP&L and Telemetric installed updated digital cellular modems, firmware and antennas to the original analog RTMs for more robust radio performance and remote troubleshooting. All system devices, such as capacitor or recloser controls interface with the RTM through a serial connection.
The RTM is based on preconfigured models that interface to a specific DNP points list at the intelligent electronic device (IED). An RTM reports its model to the PowerVista website and delivers the preconfigured DNP points to the PowerVista users. This approach makes deployment scalable, secure and cost-effective. After an RTM is programmed, it is ready for field use.
These preconfigured DNP models allowed KCP&L to deploy hundreds of IEDs quickly, efficiently and securely. The devices covered many applications from various products and manufacturers. These applications seamlessly integrated into the Sensus cloud.
DNP Alarms and SCADA
PowerVista provides alarms to users through e-mail, pagers and other portable electronic devices. This approach worked well for KCP&L engineers and technicians responding to maintenance alarms during a typical business day. Distribution dispatchers, however, needed a different solution with better visibility for higher profile alarms through a more conventional SCADA alarm solution.
A solution was readily available because KCP&L had co-funded the development of the Telemetric SCADA-Xchange application. It uses a secure virtual private network connection between Telemetric and KCP&L to deliver alarms into the KCP&L SCADA system. The optional SCADA-Xchange module works in parallel with the PowerVista application, enabling SCADA monitoring and distribution equipment control using open protocols such as DNP3.
KCP&L noticed a marked responsiveness to high-level alarms such as automated recloser trip and close alarms. Users received DNP alarms in ways that also supported existing processes.
Beyond SCADA Functionality
KCP&L maintains employee user accounts for the wireless DA system and configures settings that manage and control Web-based access by job functions. The website also records who logs onto the hosted server application and tracks user actions. Once on the system, technicians have many options for monitoring and sending commands to any networked device. The Web interface displays current device status, including all digital and analog inputs and control outputs, as well as historical data. Displays focusing on relevant information can be customized for device types and status.
With a two-way network configured to communicate with site components, users monitor and control devices from remote or central locations without dispatching linemen or technicians. An integrated historian records all system events.
In the case of a recloser, distributed networking can provide enhanced functionality beyond what a normal recloser can achieve, such as:
- Centrally monitor and report device switch position and recloser status,
- Transmit recloser control commands,
- Centrally monitor and report statistics,
- Report normal load and fault current values per phase and fault trip alarms, and
- Increase physical security reporting, such as when a door is opened.
|Bob Sloan, lead splicer, and Larry Black, journeyman cable splicer, use the PowerVista website and SCADA X-Change to view real-time operating data from automated network protectors installed on KCP&L’s underground system.|
KCP&L co-funded various user-friendly PowerVista website applications to make it more convenient to get alarms, data and applications frequently used by dispatchers, engineers and technicians.
Success Stories, the Business Case and What’s Next
Successful utility technology applications are measured by their positive effects on utility operations, customer satisfaction and safety and efficiency improvements. KCP&L is pleased that its DA program has excelled in these areas, including:
- Capacitor Automation: This was one of the initial DA programs implemented at KCP&L. KCP&L now uses DA to monitor and control approximately 2,000 automated capacitors on the system. Expensive and cumbersome capacitor patrols are mitigated, as alarms guide line workers to specific sites to address specific repairs.
- Capacitor Control: KCP&L and Sensus recently completed development of the Sensus TC032 capacitor control. This control uses a new-generation RTM design and supports remote set point changes and remote firmware upgrades. Because the RTM is integrated into the product, this DA device cost effectively provides advanced features.
- Underground Network Automation: Based on underground network operational and safety challenges, KCP&L automated all network protectors to allow remote monitoring and control. This began in 2005 and was the first DA industry rollout for an underground network application. KCP&L cable splicers now are safer because KCP&L dispatchers have replaced manual tasks with remote control switching. Dispatchers regularly monitor and address alarms and abnormal conditions.
- 34-kV Recloser Automation: KCP&L upgraded its 34-kV distribution system by installing solid dielectric reclosers and new electronic controls with RTMs. KCP&L distribution dispatchers send remote control switching commands to perform routine switching. Faulted line sections are isolated, and the system is reconfigured to quickly restore service. KCP&L has driven down its average 34-kV outage duration by 55 percent (see Figure 1). In addition, a recent study of the KCP&L South District shows customer minute interruptions (CMIs) for its 34-kV operating system have been driven down by 82 percent (see Figure 2).
Since 2008, the PowerVista applications continue to expand and progress as Sensus refines and augments hosted, private cloud services. KCP&L and Sensus are now working on a new project that will provide real-time operating information on a line diagram format while also providing advanced alarm and operating information not commonly used on energy management systems.
|Larry Black, KCP&L journeyman cable splicer, leverages analog data and digital alarms from PowerVista and SCADA X-Change to effectively target maintenance and operating support for KCP&L’s underground automated network system.|
KCP&L’s DA business case has increased customer satisfaction, improved system performance, improved safety and reduced operations and maintenance costs.
Carl R. Goeckeler, P.E., is KCP&L’s lead distribution automation engineer. Over the past two decades, the KCP&L DA group has partnered with several suppliers to develop or improve various DA control and communications applications widely used in the electric utility industry.
This article contains references to both Telemetric and Sensus. Sensus purchased Telemetric in 2009. References to Telemetric are historical.
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