Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
CAN CSA C61000-3-6-09 (2018): Emission Limits for Distorting Installations in MV, HV, and EHV Power Systems
A Technical Guide to Canadian Adoption of IEC 61000-3-6 for Harmonic Emission Assessment
1. Scope and Application
CAN CSA C61000-3-6-09 (2018) is the Canadian adoption of the international standard IEC 61000-3-6, part of the IEC 61000 series on electromagnetic compatibility (EMC). This standard provides a systematic framework for assessing and limiting harmonic emissions from distorting installations connected to medium-voltage (MV), high-voltage (HV), and extra-high-voltage (EHV) public power systems.
The standard applies to installations that draw non-sinusoidal currents—such as variable speed drives, uninterruptible power supplies, arc furnaces, large rectifiers, and inverters—and that may degrade power quality on the shared supply network. It is intended for use by network operators, planning engineers, and customers when evaluating new connections or upgrades to existing ones. The document outlines a staged assessment procedure, from simplified checks based on installation size to detailed studies with harmonic simulation.
Tip: Although CAN CSA C61000-3-6-09 (2018) is based on IEC 61000-3-6, users should consult the Canadian deviations, especially regarding base voltage levels (e.g., 60 Hz system frequency) and local regulations on power quality.
2. Technical Requirements and Planning Levels
The core of the standard is the concept of planning levels for harmonic voltages. These are compatibility targets set by the system operator to ensure that the cumulative harmonic distortion from all connected distorting installations remains within acceptable limits. Planning levels are defined for individual harmonic orders (odd and even) up to the 25th order and for total harmonic distortion (THD).
Table 1 below gives the planning levels for harmonic voltage distortion (in percent of the fundamental voltage) as referenced in CAN CSA C61000-3-6-09 (2018) for typical MV and HV/EHV systems.
| Harmonic order (odd non‑triplen) | MV (1 kV < V ≤ 35 kV) | HV/EHV (V > 35 kV) |
|---|---|---|
| 5 | 5.0 | 3.5 |
| 7 | 4.0 | 3.0 |
| 11 | 3.0 | 2.0 |
| 13 | 2.5 | 1.5 |
| 17 | 2.0 | 1.5 |
| 19 | 2.0 | 1.0 |
| 23 | 1.5 | 1.0 |
| 25 | 1.5 | 1.0 |
| Odd triplen (3, 9, 15, 21) | 2.0 | 1.0 |
| Even (2, 4, 6, … , 24) | 1.0 | 0.5 |
| THD | 6.5 | 5.0 |
The emission limits for an individual installation are derived from the planning level, the short-circuit capacity at the point of common coupling (PCC), and the agreed power capacity (Sa). The standard defines a three-stage assessment process:
- Stage 1 (Simplified): If the installation’s power is small relative to the system short-circuit power, it is assumed to comply without detailed study.
- Stage 2 (Detailed allocation): Emission limits are calculated based on the installation’s agreed power and the system’s ability to accept harmonics.
- Stage 3 (Mitigation): If Stage 2 limits would be exceeded, the customer must implement harmonic mitigation (e.g., filters, higher pulse number) and demonstrate compliance.
Important: Planning levels are not mandatory limits; they are engineering targets. The actual permissible emission levels are negotiated between the system operator and the customer, but they must not cause the total distortion to exceed the planning level at the PCC.
3. Implementation Highlights for Canadian Systems
CAN CSA C61000-3-6-09 (2018) was approved as a National Standard of Canada by the Standards Council of Canada. Key implementation aspects include:
- System frequency: The standard is adapted for 60 Hz operation, unlike the 50 Hz basis of the original IEC document. All harmonic order references remain unchanged, but time constants and filter designs should be adjusted accordingly.
- Voltage levels: Canadian utility practices define MV as 4.16 kV to 44 kV, HV as 69 kV to 230 kV, and EHV as above 230 kV. The standard’s planning levels are generally applied at these boundary points.
- Coordination: The system operator is responsible for establishing overall harmonic planning levels for the network; the customer must demonstrate that the proposed installation’s harmonic currents do not exceed the allocated emission limit.
- Existing installations: The standard also provides guidance for assessing the contribution of existing distorting installations when planning network expansions or new connections.
Benefit: Adopting CAN CSA C61000-3-6-09 (2018) promotes consistent harmonic management across Canadian jurisdictions, reduces the risk of harmonic resonance and equipment overheating, and facilitates the connection of renewable energy systems with power electronic interfaces.
4. Compliance Notes and Assessment Process
Compliance with CAN CSA C61000-3-6-09 (2018) is typically a prerequisite for connecting a distorting installation to a public utility grid. The assessment process involves the following steps:
- Data collection: Obtain system parameters (short‑circuit power, background distortion, existing loads) and installation data (rated power, harmonic spectrum of the load).
- Stage 1 screening: Check if the installation’s size meets the simplified criteria (e.g., power less than a defined fraction of short‑circuit power). If yes, compliance is assumed.
- Stage 2 detailed allocation: Calculate the permissible harmonic current for each harmonic order using the formula:
Ih,limit = Uh,plan × SSC / (√3 × Un × h)
where Uh,plan is the planning level for harmonic h, SSC is the short‑circuit capacity at the PCC, Un is the nominal line voltage, and h is the harmonic order. - Stage 3 mitigation: If the expected emissions exceed the limits, the installation must be redesigned or fitted with passive/active filters or other mitigation to reduce harmonic injection.
- Verification: Compliance can be verified by measurement (according to IEC 61000-4-7) or by simulation using validated models.
| Harmonic order (h) | Permissible current (A) |
|---|---|
| 5 | 11.5 |
| 7 | 8.9 |
| 11 | 3.5 |
| 13 | 2.1 |
| THD | 13.2 (total, ~0.6% THD voltage) |
Caution: Exceeding the emission limits can lead to excessive voltage distortion, malfunction of sensitive equipment, overheating of capacitors and transformers, and potential resonance conditions. Utility operators may refuse connection or impose additional requirements if limits are not met.
The standard also emphasizes the need for continuous monitoring and periodic reassessment, especially when the network conditions change or when additional distorting loads are added.
Frequently Asked Questions
Q: What is the difference between IEC 61000-3-6 and CAN CSA C61000-3-6-09 (2018)?
A: CAN CSA C61000-3-6-09 (2018) is a national adoption of IEC 61000-3-6, modified for Canadian conditions. The main differences include operation at 60 Hz (instead of 50 Hz), alignment with Canadian voltage classifications, and references to Canadian electrical codes. The technical content and staged assessment process are otherwise equivalent.
A: CAN CSA C61000-3-6-09 (2018) is a national adoption of IEC 61000-3-6, modified for Canadian conditions. The main differences include operation at 60 Hz (instead of 50 Hz), alignment with Canadian voltage classifications, and references to Canadian electrical codes. The technical content and staged assessment process are otherwise equivalent.
Q: What are planning levels and how are they set?
A: Planning levels are internal quality targets set by the system operator for harmonic voltage distortion at the PCC. They are not statutory limits but are used to allocate emission allowances to individual customers. The values in Table 1 are typical; each utility may define its own planning levels based on network characteristics and desired quality of supply.
A: Planning levels are internal quality targets set by the system operator for harmonic voltage distortion at the PCC. They are not statutory limits but are used to allocate emission allowances to individual customers. The values in Table 1 are typical; each utility may define its own planning levels based on network characteristics and desired quality of supply.
Q: Who is responsible for demonstrating compliance with emission limits?
A: The customer (or developer) proposing the distorting installation is responsible for providing harmonic data, performing the assessment (Stage 1, 2, or 3), and, if necessary, designing and installing mitigation measures. The system operator reviews the study and may request verification measurements after commissioning.
A: The customer (or developer) proposing the distorting installation is responsible for providing harmonic data, performing the assessment (Stage 1, 2, or 3), and, if necessary, designing and installing mitigation measures. The system operator reviews the study and may request verification measurements after commissioning.
Q: Can the standard be used for low-voltage (LV) installations?
A: No. CAN CSA C61000-3-6-09 (2018) applies only to MV, HV, and EHV systems. For LV installations, the applicable standard is CAN CSA C61000-3-2 (for equipment ≤ 16 A per phase) or CAN CSA C61000-3-12 (for equipment 16 A to 75 A per phase), which refer to emission limits for individual equipment connected to low-voltage public supply networks.
A: No. CAN CSA C61000-3-6-09 (2018) applies only to MV, HV, and EHV systems. For LV installations, the applicable standard is CAN CSA C61000-3-2 (for equipment ≤ 16 A per phase) or CAN CSA C61000-3-12 (for equipment 16 A to 75 A per phase), which refer to emission limits for individual equipment connected to low-voltage public supply networks.
Published 2026. This technical summary is for informational purposes and is not a substitute for the full standard.