Cathodic Protection

Next Generation Transformer-Rectifiers for Cathodic Protection Applications

Corroconsult UK Limited are proud to announce a new product line.

This next generation of transformer-rectifiers offer the user absolute control over the TRs configuration in real-time with the added benefit of in-built remote monitoring of key measurements.

The TRs can be viewed and configured in real-time through web based applications that are compatible with Windows / Macintosh / Android / iOS platforms.

Each initial order is provided with a lifetime single user access to the online database (additional lifetime user licenses can be purchased separately). There are no hidden ongoing subscription costs.

Each unit can be designed specifically to client requirements and is assembled and tested in the UK by Corroconsult personnel in accordance with the Company Quality Management System (ISO 9001-2015).

Take control of your impressed current cathodic protection (ICCP) systems.

Contact us for a live demonstration via video conferencing.

The Importance of Electrical Isolation

Defining "Electrical Isolation" for a Cathodic Protection System

With respect to cathodic protection systems, the term "electrical isolation" relates to confining the (cathodic) protective current to the structure being protected.

In terms of electrical separation this could mean isolating;

  • Two (or more) cathodic protection systems from one another
  • Buried / immersed structures from above ground appurtenances
  • Cathodically protected structures from earthing systems
  • Owner / Operator interfaces

Electrical isolation is a key factor in the successful application of cathodic protection where it has been included at the design stage. For the purposes of this blog article we assume that the structure is intended to be electrically isolated.

That is not to say that electrical isolation is always required, as long as the designed system has taken this into account.

There are times when it may not be desirable, or even practical, to isolate protected from unprotected structures. Examples are refineries, industrial plants, large tank farms and similar complex facilities. 

How to Electrically Isolate the Cathodically Protected Structure

Commercial fittings for providing electrical isolation of pipework include;

  • Insulating Flange Kits (IFK)
  • Monolithic Isolation Joints (IJ)
  • Non-metallic pipe sections

Cathodically protected structures can be electrically isolated from earthing systems via;

  • Decoupling Devices

Other solutions, e.g. non-conductive membranes, are available as methods of electrical isolation depending on the system in question.

Insulating Flange Kits (IFK)

Insulating Flange Kit (Exploded View) resized.jpg

The kit comprises of the following;

  • Insulating Gasket
  • Non-Metallic Sleeves for Assembly Bolts
  • Non-Metallic Washers
  • Metallic Washers
  • Nuts & Bolts

Monolithic Isolation Joints (IJ)

Monolithic Isolation Joint resized.jpg

The isolation joint is fabricated as a ready to install section of pipework.

The joint consists of;

  • Forged Rings
  • External Coating
  • Internal Coating
  • Adhesive Sealant
  • Di-Electric Filler
  • Insulating Rings
  • O Rings

Decoupling Devices

Corroconsult recommend only solid-state devices, as this eliminates the maintenance requirements and hazardous electrolytes of electrochemical polarisation cells.

acdd.jpg

Solid-state DC decoupling devices can be used for;

  • Electrically isolating from from utility earthing (grounding) systems
  • Electrically isolating from electrical equipment earthing (grounding) systems
  • Induced AC voltage mitigation
  • Isolation joint protection

How can electrical isolation be compromised?

Incorrect Installation

An incomplete kit installation for an IFK will result in the flanged joint being electrically continuous.

Earthing / Grounding

The most common failure of installed electrical isolation is through incorrect earthing of cathodically protected structures.

New ISO 20313 Standard Released - Cathodic Protection of Ships

The new ISO 20313 standard for the Cathodic Protection of ships chaired by Ken Lax was published on 30 January 2018.  This is a major achievement for the working group and especially for the UK mirror group participants (Pat Lydon, Winston Shepherd and Andrew Willis). 

 
Marine_Ship_01 resized.jpg
 

The plenary meeting of ISO Technical Committee (TC) 8 and Sub Committee (SC) 8 – Ship design met on 31 January 2018 and complimented the working group on meeting all the deadlines and producing a good standard. 

The working group has now been disbanded, although the Chairman of TC8 SC8 requested Ken to remain on the sub-committee to provide assistance.

The new Standard is available for download here: https://www.iso.org/standard/67645.html