CSA Approval Requirements for High Voltage Equipment in Ontario

Canadian Standards Association (CSA) is a non for profit organization accredited for Standard Council of Canada (SCC) to develop Canadian codes and standards. Electrical equipment sold in the market and installed in Ontario shall bear a CSA label which means they have been manufactured and tested according to the relevant CSA standard.

Custom made electrical equipment that are not type tested for mass production, can be factory tested or field tested by CSA, ESA (Electrical Safety Authority in Ontario) or other testing and inspection companies accredited by SCC.

ESA is the electrical safety authority in Ontario responsible for the inspection and approval of all electrical installations in the province.

Conformance with CSA is generally included in the specifications prepared for electrical equipment. However, CSA sticker is not mandatory for high voltage equipment.

For high voltage electrical equipment, the following two provisions are generally included in the specifications in order to meet the code requirements:

1- The high voltage equipment name plate shall include the CSA and/ or other internationally recognized standard the equipment is manufactured and tested to.

2- The control panel(s) shall bear a sticker of an accredited testing facility (CSA or others) to verify the compliance with the applicable CSA standard.

In some cases, the requirement of a CSA blue sticker is added to the purchase order to comply with the second provision above. 

The Blue Sticker indicates that the electric product is tested and meets CSA Group Special Publication SPE-1000. As such, the control panel should have blue sticker otherwise, the product does not meet PO requirement. 

Here is the typical sample of blue sticker affixed on control panel.

CSA Blue sticker is a special inspection label which indicates that the electric, non-healthcare product was tested and has met CSA Group Special Publication SPE-1000, Model Code for the Evaluation of Electrical Equipment, and the Canadian Electrical Code for installations and use. However, the CSA blue sticker is one of the labels that can be used to ensure the control panel meets the relevant code requirements.  

There is a CSA red sticker/ label - shown below- that can also be used for this application. CSA Red sticker is another special inspection label which indicates that the control panel was tested and has met CSA Group Special Publication SPE-1000, Model Code for the Evaluation of Electrical Equipment, and the Canadian Electrical Code for installations and use.

As stated above, there are a number of facilities that can inspect the control panel(s) of high voltage equipment and provide their relevant sticker which would be acceptable by ESA. 

According to ESA product approval card, the recognized certification markings are as follows:

According to the same document the following are the recognized panel-only field evaluation markings:

For example, for any HV transformer installed in Ontario, recognized inspection stickers would be needed for control panel(s) only. As far as the control panel is certified and the transformer nameplate refers to the applicable standards the transformer is built and tested to, the transformer would meet the requirements and will be approved and pass the inspection by the local ESA inspector.

Orange sticker issued by Electrical Safety Authority (ESA), or stickers issued by QPS or Entela depicted above can also be used in lieu of a CSA blue sticker and will be acceptable by local ESA inspector at site.

The certification agencies recognized by ESA are as follows: 

Canadian Standards Association (CSA)Curtis-Straus LLCElectrical Safety Authority Field Evaluation (ESAFE)FM ApprovalsIAPMO R&T, IncIntertek Testing ServicesLab Test Certification IncMet Laboratories Inc. (MET)NemkoNemko CanadaNSF InternationalOMNI Environmental Services Inc.QPSQuality Auditing InstituteSGSTUV AmericaTUV RheinlandUnderwriters Laboratories of Canada (ULC)Underwriters' Laboratories Inc.

The following is the list of field evaluation agencies recognized by ESA. 

Canadian Standards Association (CSA)Electrical Safety Authority Field Evaluation (ESAFE)Intertek Testing ServicesLab Test Certification IncMet Laboratories Inc. (MET)NemkoQPSQuality Auditing InstituteTUV AmericaTUV RheinlandUnderwriters Laboratories of Canada (ULC)

References:

  -  ESA Bulletin 36-1-21

  -  CSA Website: http://www.csagroup.org/services-industries/marks-labels/csa-marks/

  -  Standard Council of Canada Website: https://www.scc.ca/

Partial Discharge Test

In terms of interpretation of partial discharge measurements, the results shall be considered acceptable and no further partial discharge tests required under the following conditions:

a) The magnitude of the partial discharge level does not exceed 500 pC during the 1 h test period.

b) The increase in partial discharge levels during the 1 h period does not exceed 150 pC.

c) The partial discharge levels during the 1 h period do not exhibit any steadily rising trend, and no sudden sustained increase in the levels occurs during the last 20 min of the test.

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Reference:

IEEE C57.12.90: Test Code for Liquid-Immersed Distribution, Power, and Regulating

Oil Containment Dimensions and safe distance between Power Transformers

Oil Containment Dimensions 

and 

safe distance between Power Transformers 

The effective volume of the oil containment shall be greater than or equal to the 110 per cent of the transformer oil. In case the oil containment is filled with gravel, the above percentage shall apply to the available volume of the containment (air pockets) for oil in case of an oil spillage. 

The volume of oil of a specific size transformer, might be different for different manufacturers. The BIL level can also affect the size of the tank and consequently the volume of transformer oil.

For a typical 20 MVA transformer with an Off-load tap changer,  the volume of oil  can be 5000 US Gallons or almost 19000 liters. 

Another important parameter in the design of the containment is the clearance between the transformer and containment wall. According to IEEE recommendation, the minimum horizontal distance of any oil contained part of the transformer and the containment wall would be 1.5 meters. 

Factory Mutual -the prominent insurer of industrial premises- is a good source for safty regulation and clearances and measure to mitigate the risk of hazards in heavy industrial projects including emergency generators, transformers and other station equipment.

Recommendations on the clearances of typical 20 MVA transformer would be as follows:

Between the transformer containment and a combustible wall: 25 feet (7.62 meters)

Between the transformer containment and a 2 hours fire-resistant wall: 15 feet (4.57 meters)

Between two transformers: 25 feet (7.62 meters) 

.

Note 1:  A brick wall is considered to be combustible and do not offer a 2 hours fire resistance.

Note 2: A fire wall would be required to install transformers closer to each other. Minimum distance between the transformer and the fire wall would be 1.5 meters.

Masoud Kashani

February 2014 

Gas Trapped in Distribution Transformers

Distribution transformers are generally sealed tank with gas space these days as opposed to the previous generation of conservator type transformers.

The oil filling of tanks of these transformers is made in open air, usually with a simple hose in the transformer. This type of oil filling results in trapping air in the oil, the windings and the core assembly and structure. Trapped air consists of Nitrogen, Oxygen and a small quantity of Carbon Dioxide.

This does not happen in high voltage power transformers since they are filled under vacuum and they go through an extensive degassing process.

The trapped air in distribution transformers may vary greatly from one transformer to the other and with time. The trapped air will migrate at different speed to the gas space.

During the transformer test, discharges might happen between the winding and the tank due to poor workmanship or insulation failure. In these cases different hydro-carbon gases are generated and added to the gas content due to the spark in the oil.

After the required retrofit action on the failed insulation, the gas content of the oil is measured and analyzed by experts to verify the safe operation of the transformer under the tests and normal operation of the transformer.

Based on the above-mentioned oil filling procedure, one should not be concerned by Nitrogen and Oxygen in analysis of dissolved gas.

In the test result of the gas content of these transformers, five gases that are more of concern are: Hydrogen, Methane, Ethane,Ethylene and Acetylene. Also, the ratios that shall be taken into account more seriously are: CH4/H2, C2H2/C2H4, C2H2/CH4, C2H6/C2H2 and C2H4/C2H6.