POWER MONITORING

1. Power Quality

Power quality involves a broad range of variations in the electric power supplied to utility customers. Non-compliance with power quality standards from distributed resources can lead to penalties for both utilities and customers. This is due to the fact that distorted supply voltage causes devices to draw non-sinusoidal currents, leading to various technical issues such as overheating, malfunction, and premature aging. Additionally, non-sinusoidal currents induce thermal and insulation stress on network devices, including transformers and feeder cables.

Poor power quality results in financial losses through equipment downtime, increased maintenance activities, and reduced equipment lifespans. It is often linked to wiring problems, grounding issues, switching transients, load variations, and harmonics.

To manage power quality effectively, reliable monitoring and reporting methods are essential. Most utilities have adopted power quality standards to develop and enforce regulations.

Key industry standards include IEC 61000-4-30 Class A and Class S, IEC 61000-4-7 for harmonic measurements, and IEC 61000-4-15 for flicker measurement. These standards provide a unified understanding of power quality in electrical networks and assure users of accurate data for resolving problems related to events. They are crucial in heavy current measurement, offering reliability, accuracy, and extended service life guarantees.

In electrical networks, key indicators of electrical health include voltage sags, swells, flickers, variations in nominal ratings, and distortions due to harmonics. Thus, the accuracy of current measurements is critical to power quality, with precise current measurement being key to providing reliable and repeatable results. The growing demand for wide frequency range, revenue-grade current transformers for high accuracy metering is driven by the need to enhance network power quality for reliable outcomes.

There are three types of power quality meters: self-contained (direct drive), current transformer rated (1A:5A), and external current transformers (333mV:100mA).

J&D offers comprehensive power quality solutions, including Revenue-Grade CTs (Current Transformers).

2. AC metering

There are three types of electric smart meters: self-contained (direct drive), current transformer rated (1A:5A), and those with external current transformers (333mV:100mA).

Most revenue-grade smart meters used in homes or commercial buildings are self-contained. For improving power distribution efficiency, power meters and multi-circuit energy monitors typically use current transformer-rated or external current transformers.

The majority of energy efficiency applications aim for resource conservation, climate protection, and, most commonly, cost savings. Energy efficiency is about gaining a better understanding of how and where energy is consumed and using this data to make effective adjustments in energy usage. By adopting more efficient technology or production processes, a higher level of energy efficiency can be achieved. Auditing the energy efficiency of a home or building before and after these upgrades is crucial for verifying performance improvements.

J&D offers a variety of power and energy meters, along with remote CTs, capable of tracking energy consumption in both residential and commercial settings. For more information on J&D’s line of current transformers and energy efficiency meters, visit the application products information section below.

How to Choose the Right Current Transformers for
Power Quality and AC Metering?
Identify Key Factors
Rigid Construction
  • If you need a solid core, the conductor must be inserted through the window.
    Note that with a split core, you must disconnect the conductor to feed it through the window of the CT.
Compact and Lightweight
  • Consider split core transformers.
Limited Space or Unusual Conductor Shapes
  • Rogowski split core transformers are suitable.
Ease of Installation
  • Split core and Rogowski coil CTs can be installed without disconnecting wires.
Meter Requirements
  • Different meters might necessitate specific current transformer outputs and accuracies. Choose CTs based on the meter's requirements.
CT Outputs
  • Determine whether your meter is designed for Voltage or Ampere input. Common standards include 333mV, 100mA, 1A, and 5A.
Rogowski Coil Compatibility
  • Check if your meter can work with flexible Rogowski coils, with or without an amplifier/integrator. Common integrator outputs are 333mV, 100mA, 1A, or 5A.
Need for Revenue-Grade CTs
  • For applications like tenant submetering or billing where accuracy is crucial, select CTs meeting IEEE C57.13 Class 0.6 and 0.3 or IEC61869-2 Class 0.5S and 0.2S standards.
Power Quality Monitoring CTs
  • Ensure compliance with IEC61000-4-30 standards. High-specification, flexible CTs are ideal for measuring AC current in power metering and quality analysis, especially for harmonics and power quality.
CT Safety Certification
  • Compliance with UL61010-1 standards is essential, especially for energy monitoring equipment. Consider CTs certified with UL61010-1 or UL 2808 for enhanced safety in commercial submetering.

3. DC metering

There are two types of DC smart meters: self-contained (direct drive) and those that use external DC voltage and DC current transducers.

Significant demand for DC metering has been observed in renewable energy applications, such as solar panel metering, Energy Storage Systems (ESS), electric vehicle charging stations, and others.

Monitoring these applications is crucial for tracking energy production and quantifying losses before conversion. It also aids in measuring efficiency and performance.

J&D provides comprehensive DC metering solutions, including remote DC current and DC voltage transducers.

How to Choose the Right Current Transducers
for DC Metering?
1) First, Prioritize Important Factors
  • Rigidity:
    A solid core can be your solution. However, for a solid core, the conductor must be inserted through the window. With a solid core, you will need to disconnect the conductor to feed it through the window opening of the DC CT.

  • Compact and Lightweight:
     A split core could be your solution. Split core DC CTs are designed for easy installation without the need to disconnect any wires.

  • Meter Requirements:
    With so many variables, selecting the exact right DC current transducers for a DC power monitoring project can be challenging. Different meter models necessitate the checking and selection of the output and accuracy of the DC current transducers. The choice of meter can significantly influence the choice of DC CT.
2) DC CT Outputs - Which Input Does Your Meter Require? Voltage or Ampere?
  • Common industry standards include 471mVdc, 4Vdc, and 100mAdc.
3) Do You Require a Revenue-Grade DC CT?
  • There is significant demand for DC static meters (IEC 62053-41 ED1) in renewable energy applications such as solar panel metering, Energy Storage Systems (ESS), Electric Vehicle charging stations, and others.
4) Do You Have DC CT’s Safety Certification?
  • Compliance with UL61010-1 standards is essential, especially for DC energy monitoring equipment. If you currently use or plan to use DC CTs, ensure they comply with UL61010-1. DC CTs with UL61010-1 certification enhance the safety of operating DC power meters, particularly those used for DC submetering.