Circuit breakers are used in nearly every electrical system and perform the vital function of interrupting current flow in the event of an overload or short circuit. But the emergence of Internet of Things (IoT) technologies has expanded the capabilities of circuit breakers, creating the new category of "intelligent circuit breakers." Intelligent circuit breakers enable deeper electrical power system visibility, which allows for a more efficient means of monitoring electrical systems and offers the ability to generate power management data and perform predictive diagnostics. Intelligent circuit breakers can provide electrical system data to determine where and why an electrical fault occurred, making it easier and faster to troubleshoot a problem. By adding IoT connectivity and intelligence to a common electrical system component, analytics can be performed within the breaker to move from simply data collection to system-wide actionable knowledge. In this spotlight article, we examine how IoT connectivity for circuit protection lays the foundation for system-wide intelligence, featuring the IoT-enabled Power Defense molded case circuit breaker made by Eaton Corporation.
The Power Defense family of molded case circuit breakers incorporate Power Xpert Release (PXR) electronic trip units with safety and protection features. The product family has ratings from 15 to 2500 A, featuring thermal-magnetic and electronic circuit breakers and modular field-installable accessories. Power Defense molded case circuit breakers include six frame sizes. Interrupting ratings are optimized for power distribution. The Power Defense molded case circuit breakers feature modular accessories designed for customization of the breaker. Internal accessories include auxiliary switches, alarm switches, shunt trips, and undervoltage releases. External accessories include multiple cable terminal options, multiwire terminals, terminal shields, interphase barriers, manual operating mechanisms, and remote/electrical operators. Power Defense breakers meet the requirements of UL, CSA, CE, and CCC.
Power Xpert Release (PXR) Electronic Trip Units
Embedded in the Power Defense MCCB family are Power Xpert Release (PXR) electronic trip units for low-voltage commercial and industrial applications. The trip units simplify communications and protection, as well as supporting energy metering. The trip units can be configured for an individual circuit breaker, including changing set points, setting up energy metering, or gathering power system information. The trip units have a visual interface for performance metrics such as metering, battery life, zone selective interlock settings, and circuit breaker health. PXR electronic trip units are microprocessor-controlled, including algorithms that notify when your power distribution system needs to be maintained or replaced.
PXR trip units also offer programmable relay alarms, which provide situational awareness to preempt impending system failures. Circuit breaker “health” algorithms provide diagnostic indicators needed to monitor the status or health of an individual device. Data can then be communicated through the PXR trip unit to the building management system, facility control system, or the cloud.
Using Power Defense circuit breakers equipped with PXR trip units, users are able to gather a range of data, including, but not limited to: Vibration, Average asset utilization, Production output, Off/on status of devices, Voltage regulation, Power watt peak day, Humidity, Conformance data, Air pressure, Material thickness, Stroke speed, Machine type, Cure time, Water flow, Temperature, Material waviness, Real-time voltage anomalies, Weekend energy consumption, Plant power consumption pattern, Energy consumption, Operating time, Peak demand cost, CO2 emission, Daily peak power, and Total energy cost.
The PXR trip unit, with its current sensors and a trip actuator, is a subsystem of a circuit breaker that provides a wide variety of protective functions. The PXR analyzes signals from the current sensors; if current level and time delay settings are exceeded then the PXR will trip the circuit breaker. The overload and short circuit tripping characteristics for a specific circuit breaker are determined by the current rating and user selected protection settings. Metering uses those same current sensors to monitor and record current. Additionally, the PXR supports a waveform capture mechanism by which you can monitor your systems currents and voltages. The communication systems provide real-time status and data from the PXR for integration with business information systems, control schemes, or other systems used by service personnel.
Trip Unit Features
The trip unit has key features that enable safety, protection, monitoring, and IoT connectivity. They include the following:
The Arcflash Reduction Maintenance System: uses a separate dedicated trip circuit that provides faster interruption times than the standard “instantaneous” protection. The technology is based on the realization that, when working on energized electrical equipment, a fault that occurs within it needs to be cleared as quickly as possible. The system provides the fastest possible breaker clearing time, which results in the lowest arc energy exposure to the worker. When Arcflash Reduction Maintenance System is enabled, the internal circuit breaker digital logic is bypassed by an even faster analog tripping circuit. Work locations downstream of a circuit breaker with an Arcflash Reduction Maintenance System unit can have significantly lower incident energy levels. This safety feature can enhance the safety of your personnel and decrease personal protection equipment (PPE) requirements to enhance productivity.
Zone Selective Interlocking (ZSI): is a communication scheme used with electronic trip units for circuit breakers to improve the level of protection in a power distribution system. The purpose of ZSI is to speed up tripping for some faults without sacrificing the coordination of the system and interjecting nuisance trips into the system. ZSI communicates when a phase or ground fault is present. The breaker closest to the fault will override any customer-defined delay setting and open instantaneously to clear the fault, allowing line-side breakers to remain closed and online. ZSI is also a solution for reducing arc flash incident energy when a fault is present. The PXR trip unit displays ZSI signal indication when the system is engaged, allowing network integrity testing and providing operational status.
Enhanced Ground Fault Protection and Coordination: Expanded protection of ground fault increases coordination capabilities and provides the ability to turn protection off. Ground fault trip units combine trip, alarm, and OFF in every unit, with programmable relays for alarm or pre-alarm functionality. Expanded time profile selections include I2t and flat response profiles for more coordination options.
Breaker Health Feature and Programmable Alarms: The breaker health monitor feature and programmable alarms enable you to perform predictive and preventive maintenance on your power distribution system prior to component failure. A health status algorithm monitors parameters including short-circuits, overloads, operations, temperature, and run-time. These parameters can provide an overall picture of the condition of the breaker that can be used for predictive maintenance and furthermore system reliability. It also provides real-time evaluation of breaker condition by tracking and analyzing diagnostic details including breaker operations, short-circuit fault levels, operational time, internal temperature, and overloads. At the breaker, monitoring of operating and ambient conditions can be coupled with electronic sensors that communicate health status The data may be retrieved locally or remotely via control or communication systems for further analysis and data recording.
Standard Embedded Serial Communications: Standard embedded serial communications and optional Communications Adapter Modules (CAM) allow for easy connections over the serial protocol Modbus-RTU, Ethernet protocols such as Modbus-TCP (via CAM), or industrial protocols such as Profibus-DP (via CAM). The communication features, in conjunction with the metering, health, and control functions can be utilized in IOT-based systems or for connection to PLC building management systems, SCADA, and other cloud-based systems.
Power Xpert Protection Manager
Once installed, the Power Xpert Release trip unit can be controlled though the Power Xpert Protection Manager (PXPM) interface. This user interface allows for trip unit set up and programming, real-time reporting of power and energy metering, as well as the ability to check performance metrics, to meet your application needs. The testing features and functionality, which can be run through a personal computer, offer savings through labor hour reduction and avoiding the need for expensive proprietary testing kits. PXR trip units are equipped with micro-USB connection for secondary injection testing through your PC. You can configure trip unit settings with direct-to-trip unit or offline setup, including duplication of settings between units. You can capture waveforms, monitor real-time power and energy readings, store up to 200 events, create printable test reports, and customize display orientation.
How IoT-Enabled Circuit Breakers Provide System Wide Intelligence
Molded case circuit breakers (MCCBs) provide vital functionality for low-voltage power distribution systems and process machinery by protecting connected devices from both overloads and short circuits. MCCBs are pervasive and applied across a wide variety of systems, devices, and machinery, including panelboards, feeder pillars, switchgear, busbar trunking tap-offs, motor control centers, machine tool control panels, and standard enclosures. Simply put, MCCBs are used in nearly every application around the world for personnel, equipment protection, main, and branch circuit protection. Due to their critical placement throughout systems, how do you know when an individual MCCB has failed? Next question: in facilities that have many hundreds of MCCBs in operation, how do you go about investing the time and resources into inspecting and testing all of them?
Power Defense molded case circuit breakers equipped with Power Xpert Release (PXR) trip units are an improvement over traditional breaker inspection procedures, because they can provide key data analytics and predictive diagnostics. The parameters that are monitored by PXR trip units include short-circuits, overloads, operations, temperature, and run-time. These parameters can provide a host of individual insights, including"
- Operation data provides insight on when the breaker mechanism was last exercised, and if the mechanism was bound or jammed.
- Total number of operations can provide indication of the endurance wear on the circuit breaker mechanism and indication of contact wear.
- Number of interruptions and the magnitude of the energy interrupted are an indication contact wear indication and the arc chute condition.
- Overload interruptions have less of an effect than short-circuits, but they are included in the calculation and weigh in on the health of the circuit breaker.
- Short-circuits can be damaging to the contacts, integrity and dielectric strength of the circuit breaker. The magnitude of a short circuit event is compared to the rating of the circuit breaker and weighed as another factor in the health of the circuit breaker.
- Run-time is also considered and demonstrates how long the breaker has been in use with current flowing through it.
- The environmental temperature is one of the most important measurements; this is the highest temperature recorded and the date and time of that temperature is saved in the analysis.
A key part of intelligent power management and protection is connectivity: transforming the way systems interact with one another. Connected devices need to easily connect to each other and the outside world to transmit the data. Intelligent IoT-enabled circuit breakers like the Power Defense MCCB contain more internal sensors to provide continuous monitoring and enabling the development of an accurate picture of circuit breaker and system status. With this technology, facilities, buildings and connected factories are able to track the health of fundamental electrical system components in real-time and over time. Once data is collected, analysis can be performed through the algorithm in the trip unit, to get a sense of the device and system health.This data can then be communicated through the PXR trip unit to the building management system, facility control system, or the cloud.The real-time data can be further leveraged to support an electrical system that is more integrated and automated with the overall facility or process. Furthermore, intelligent circuit breakers will provide a new level of insight on the devices that are connected to the power distribution system, including critical information that can be used for predictive maintenance of critical systems. Leveraging this data, facilities can intervene proactively to perform critical maintenance before there is a failure, improving their productivity and cutting their operational cost.
|PDG32M0600E5CJ (with PXR 20)