High Accuracy Current and Voltage Sensors for Better Grid Control
G&W Electric’s patented sensor technology helps customers control power quality, monitoring, protection and measurement with accurate, real-time current and voltage intelligence for optimizing the grid’s power delivery and reliability. G&W Electric’s Accusense current sensing technology utilizes Rogowski coils that can measure a wide range of current analytics with high precision, from dynamic system loads to fault currents. These high accuracy current and voltage sensors provide accurate, real-time data for smart grid monitoring and situational awareness across the distribution network.
Highly Precise and Accurate Current and Voltage Sensors
The grid and industry are rapidly evolving with initiatives like distributed energy resources (DERs), microgrids, optimizing energy efficiency and resiliency, and more. G&W Electric’s patented sensor technology helps customers control power quality, monitoring, protection and measurement with accurate, real-time current and voltage intelligence for optimizing the grid’s power delivery and reliability. G&W Electric’s Accusense current sensing technology utilizes Rogowski coils that can measure a wide range of current analytics with high precision, from dynamic system loads to fault currents.
Versatility with one sensor for metering and protection applications
Safety with low energy outputs and galvanic isolation from primary
High accuracy up to 0.5 class over a wide temperature range
High frequency measurement bandwidth
Lightweight, compact size for easy installation and retrofits
Reliability with no ferroresonance
Sensors Designed for Your Needs
Power Quality & Monitoring
Today, the need for higher quality power is critically important. G&W Electric’s high accuracy current and voltage sensors have a wide, dynamic measurement range to quickly detect and remediate power quality issues. Our sensor technology allows them to respond to rapid changes in current and voltage, including high-frequency harmonics, with minimal distortion. This capability makes them suitable for monitoring harmonic content and other high frequency disturbances in distribution grids and assessing the impact on system performance. These sensors provide accurate, real-time current and voltage measurements that support smart grid monitoring, power quality analysis, and visibility into changing distribution-grid conditions.
Protection & Measurement
With the increasing integration of distributed energy resources (DERs) into the grid, continuous monitoring of current and voltage is critically important. Sensors play a crucial role in detecting and localizing faults within the distribution grid. Sudden changes in voltage levels or phase angles can indicate the presence of faults such as short circuits or line failures. Speed of response, high accuracy and reduced footprint, are added values that improve the overall performance of the platform. Compared with conventional instrument transformers, current and voltage sensing can provide a lighter, more compact form factor for applications where space and retrofit flexibility are important.
Key Benefits of G&W Electric Sensors
High Accuracy
Selected G&W Electric current and voltage sensors are available with 0.5 accuracy class; exact accuracy ratings vary by sensor model and application.
Flexible Sensor Options
Both active (externally powered) and passive (self-powered) sensor types are available, covering 7.5 kV up to 40.5 kV for indoor and outdoor applications.
Advanced Sensing Technology
Accusense sensors use Rogowski coils for current measurement and capacitive voltage dividers for voltage measurement, supporting wide measurement ranges, high-frequency response and compact sensor designs.
Multiple Applications
These sensors double as smart grid sensors and grid monitoring sensors, supporting power quality monitoring, protection, and metering-class measurement from a single device.
Explore All Sensor Products
G&W Electric’s high accuracy current and voltage sensors cover a wide range of applications, from power quality analytics and monitoring to metering-class measurement and protection.
Comparing Sensing Technology
Several sensing technologies are used to measure current in medium-voltage systems, each with different trade-offs. The table below compares Rogowski coils, the technology behind G&W’s Accusense sensors, against the alternatives most commonly discussed for this application.
| Technology | Measures | Isolation | Key Tradeoff |
|---|---|---|---|
| Rogowski coil | AC only | Inherent (coreless, no direct conductor contact) | No iron core to saturate or cause ferroresonance; needs an integrator circuit to recover a current waveform |
| Conventional current transformer (CT) | AC only | Inherent (magnetic coupling | Iron core can saturate under fault conditions and carries ferroresonance risk; heavier and bulkier |
| Hall effect sensor | AC and DC | Galvanic isolation | Accuracy can drift with temperature; well suited where DC measurement is required |
| Shunt resistor | AC and DC | None on its own (needs an isolation amplifier) | Very accurate at low currents but dissipates heat and loses accuracy as current rises |
| Closed-loop fluxgate / zero-flux transducer | AC and DC | Galvanic isolation | High accuracy and wide bandwidth, at higher cost and circuit complexity than the alternatives above |
For teams weighing a retrofit, the practical question is usually whether switching sensing technology means replacing existing switchgear. It typically does not: Accusense voltage sensor retrofits are designed to fit into existing recloser and switchgear footprints, so upgrading to Rogowski-coil-based high accuracy current and voltage sensors does not usually require a full equipment replacement.
Frequently Asked Questions
Have more questions? View our comprehensive list of frequently asked questions about sensors.
What is a medium voltage sensor?
A medium voltage sensor is a device used to measure and monitor voltage levels in the medium voltage range, typically ranging from several hundred to several thousand volts. G&W Electric has quite a wide portfolio of products rated from 7.5 kV up to 40.5 kV. Both active and passive type, for IEEE and IEC and covering indoor and outdoor applications. These sensors can support smart grid monitoring across substations and feeders by providing accurate current and voltage measurement data. For additional buyer questions, explore our medium-voltage sensor FAQs.
What is the difference between active and passive sensors?
An active sensor, uses an external power source to amplify the signal and make it available for the measurement system (relays); while a passive sensor transfer the measured quantity from the source to the measurement system without any amplification and without the need of an external power source.
How does a medium voltage sensor work?
Medium voltage sensors typically work by utilizing resistive or capacitive voltage dividers to reduce the primary voltage signal into a low-voltage proportional output, which can be easily measured and interpreted. G&W Electric uses capacitive voltage dividers for voltage sensors. For the measure of the current, G&W Electric uses Rogowski coil technology. G&W Electric uses capacitive voltage dividers for voltage measurement and Rogowski coil technology for current measurement. Together, these technologies support accurate measurement across a wide dynamic range.
Are medium voltage sensors accurate?
Yes, medium voltage sensors are designed to provide accurate measurements within their specified range. The G&W Electric portfolio has current and voltage sensors with 0.5 accuracy class per IEC standard, which means a maximum ± 0.5 % error on the measure upon the measured voltage range.
How is a Rogowski coil different from a conventional current transformer?
Unlike a conventional current transformer, a Rogowski coil has no iron core, so it does not saturate under high-current fault conditions. Both measure AC current, but Rogowski coils use a lighter, more flexible form factor that can be better suited to retrofit applications where space is limited.
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