ERA: Draft decisions on proposed changes to Technical Rules

ERA – Economic Regulation Authority

Sep 10
ERA: Draft decisions on proposed changes to Technical Rules

On 7 September, the Economic Regulation Authority (ERA) published two draft determination on separate changes to the Technical Rules proposed by Western Power in March and April 2016.  The proposed changes and draft determination decisions are shown in the tables below:

Changes to the Technical Rules proposed in March 2016.

Proposed change ERA draft decision Reasoning
Removal of 3-phase faults from credible contingency scenarios for voltages at or above 66kV (the transmission system) Approve To ensure consistency with the National Electricity Rules but with additional clarity around the treatment of 3-phase faults in power system planning
Amendments to the N-1 provisions to allow voluntary load shedding and post contingent ‘run back’ generation tripping for user agreed connections Approve Will reduce the need for network investment and improve the utilisation of the existing network whilst maintaining a safe and reliable power supply
Addition of the term “Weak in-feed fault conditions” to the Technical Rules Glossary and a new sub-clause to clause 2.9.4 setting out how quickly a protection relay and associated circuit breaker must clear a fault. Approve Will remove barriers to network connection for small embedded generators

The changes proposed in April are as follows:

Proposed change ERA draft decision Reasoning
Amendments to the wording of the Normal Cyclic Rating (NCR) criterion which outlines the permissible level of power loss following the unplanned loss of a supply transformer at a substation Not approve Western Power’s proposed text revision does not clarify the intent of the clause
The replacement of references to Electricity (Supply Standards and System Safety) Regulations 2001 with references to electricity (Network Safety) Regulations 2015 Approve Reflects most up to date regulations
Correction of an incorrect cross reference in Clause 4.2.1(a) Approve Correction only
Correction of the misspelling of the word “Distribution” in the title of Section 5 Approve Correction only
Additions to the Glossary of the Technical Rules that will allow the Rules to automatically adopt revisions to Standards and Regulations “as amended from time to time” Not approve Instead correct any references to wrongly dated standards and regulations

This draft determination follows publication of an issues paper earlier in the year.  Submissions on both the draft decision are required by 28 September 2016.