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Distribution-connected Companies

Power Quality - What it means to you

With distribution-connected companies adding new technologies and sensitive electronic equipment to their operations, Power Quality issues have become more important. Hydro One is responding to our customers' needs with a Power Quality Inquiry Reporting Process.

Since the network is interconnected, in some cases, one customer's equipment can adversely affect the quality of electrical supply to another customer. For example, large motors, arc furnaces, a large number of non-linear loads such as variable speed drives, or power factor correction capacitors, can all contribute to power quality disturbances. It's also possible that normal switching on Hydro One's network equipment may adversely affect our customers. These are only two examples of the types of power quality disturbances that Hydro One and our customers may experience.

If you are a distribution-connected customer and would like to report a power quality incident, please complete and submit our online Power Quality Incident Form.

Power Quality - What it means to us

Power Quality (PQ) refers to characteristics of electricity at a given point on the delivery path, as it relates to the compatibility between the electricity supplied on a network and the loads connected to that network. In short, everything in between "power is off" and "power is on" relates to Power Quality. Reliability differs from Power Quality. It refers to a loss of power at the delivery point only (see diagram below).

In more technical terms, a power quality disturbance is associated with the deviations in the magnitude and frequency of the sinusoidal waveform. A deviation in the sinusoidal waveform may occur when power remains on and a transmission interruption does not occur (e.g. the lights stay on, but it may flicker or dim). It can take many forms, such as: voltage sag, phase unbalance and voltage swells, transient disturbances, momentary interruptions, and long-term steady state waveform distortions. For a more detailed look at specific power quality disturbances, check out our definitions page.

Potential Problems - Minimize the risk by design

Customers should contact Hydro One for advice before upgrading major systems, adding substantial equipment or changing hours of operation so that we can help you design your facilities to work efficiently with our transmission system, thereby minimizing the risk of power quality disturbances and avoiding any adverse impact on your facilities, as well as ours.

PQ issues may arise from one or a combination of events on the transmission system, a utilities' distribution system, or a customer's own plant system/equipment. Joint co-operation between various stakeholders and Hydro One is important to address power quality incidents.