Vegetation Management

Transcription

1 Vegetation Management Revised Network Standards For Official Use Only

2 Overview Ausgrid s Compliance Requirements Vegetation Management Common Requirements (History) Industry Guideline ISSC3 What is a Network Standard? NS179 - Revised approach to Vegetation Management What has changed and why? What does this mean practically? Questions/Discussion 2 For Official Use Only

3 Ausgrid s Compliance Requirements Acts Regulations Industry Guidelines Journey Ausgrid is up to the Network Standard Ausgrid Network Standards Tree Safety Management Plan Contract Management and Application in the field 3 For Official Use Only

4 Ausgrid s Compliance Requirements 4 For Official Use Only

5 Vegetation Management Common Requirements Vegetation Management Common Requirement (VMCR) VMCR developed by Networks NSW in Developed to: Align vegetation management requirements between Ausgrid, Endeavour Energy and Essential Energy. Facilitate common contract specification. Provide an equal risk outcome across the three network operators. Based on ISSC3 (2005) but reflected recent industry experience and evolving vegetation management requirements. VMCR is basis of Ausgrid s current vegetation management contracts. 5 For Official Use Only

6 Industry Guideline ISSC3 How Ausgrid is now using the revised ISSC3 ISSC supersedes: Previous ISSC3 versions VMCR Basis of Ausgrid s proposed new vegetation management requirements (Network Standard) Basis of NS179. Ausgrid s default requirements. Developing exceptions for overhead mains which: do not conform to predefined ISSC3 clearances, but remain within the allowed guideline principles and do not establish a lesser public safety and risk outcome within scope of ISSC3 to minimise impact in sensitive locations. 6 For Official Use Only

7 What is a Network Standard? A document that describes Ausgrid s minimum requirements for planning, design, construction, maintenance, technical specification, environmental, property and metering activities on the distribution and transmission network. 7 For Official Use Only

8 What is a Network Standard? What does a Network Standard do or mean? Defines Ausgrid s requirements in terms of outcomes i.e. the end result required. Not necessarily the how to achieve the required end result (unless it has a direct impact on our assets). Not a contract specification. Often included in contract specifications as reference. 8 For Official Use Only

9 NS179 Revised approach to Vegetation Management Purpose: To define Ausgrid s requirements regarding management of vegetation in the vicinity of Ausgrid s network assets. Specifically for Urban low voltage overhead mains this draft contains Ausgrid s requirements for addressing vegetation management near these assets in a manner which balances network risk and community expectations with an aim to minimise vegetation cutting wherever the vegetation risk can be managed to a level that is ALARP. 9 For Official Use Only

10 NS179 Revised approach to Vegetation Management Where does NS179 sit in relation to ISSC3? NS179 defines how ISSC3 is to be applied in Ausgrid s particular circumstances. Vegetation management to be generally in accordance with ISSC3 (default). Other requirements in NS179 either clarify Ausgrid s requirements regarding ISSC3 or are supplementary to those in ISSC3. NS179 takes precedence. 10 For Official Use Only

11 NS179 Revised approach to Vegetation Management Regrowth Management Only cut if expected to grow into Minimum Clearance. Cutting so as to minimise the potential for regrowth. Branches may be cut outside the regrowth allowance if it will reduce the number of wounds and enhance aesthetics. No allowance for regrowth above mains Proposed: no regrowth allowance from above unless risk of growing downwards. 11 For Official Use Only

12 NS179 Revised approach to Vegetation Management Significant Limbs Exception May remain within minimum clearance to not less than 0.1m. LV ABC/XLPE, HV ABC: all spans. LV bare/covered: spans 50m. 12 For Official Use Only

13 NS179 Revised approach to Vegetation Management Why spans 50m for LV bare/covered conductor? 13 For Official Use Only

14 NS179 Revised approach to Vegetation Management Significant Limbs Generally not to be cut without first investigating other options. Allowed within minimum clearances under certain circumstances - see exceptions 14 For Official Use Only

15 NS179 Revised approach to Vegetation Management 15 For Official Use Only

16 NS179 Revised approach to Vegetation Management LV ABC/XLPE, HV ABC Exception 0.1m clearance all around Zero regrowth allowance Contact okay with foliage as well as vegetation less than 25mm diameter ( thumb-thickness ) 16 For Official Use Only

17 NS179 Revised approach to Vegetation Management LV Bare or Covered Exception 0.5m above and below ISSC3 beside (blowout) Spans 50m Regrowth allowance required however Contact with foliage from below okay (i.e. effective reduction in regrowth allowance) 17 For Official Use Only

18 NS179 Revised approach to Vegetation Management 18 For Official Use Only

19 What has changed and why? Balance risk against stakeholder requirements Risks Safety Localised Fire / Bushfire Impacts Damage Reliability Stakeholder Requirements Reduced clearances Customer satisfaction Aesthetics 19 For Official Use Only

20 What has changed and why? Risks Safety Electric shock Localised Fire/Bushfire Impacts Damage Network Vegetation Other: 3 rd party, etc. Reliability Loss of electricity supply, essential service 20 For Official Use Only

21 What has changed and why? Risk Sources Climbing of vegetation ( unauthorised access ) Damage to network Falling/movement of vegetation (due to wind) Fallen/burnt-down conductors Clashing of conductors Conductors contacting or becoming entangled with vegetation. 21 For Official Use Only

22 What has changed and why? Risk Mitigations Non-climbable vegetation could be used for tree replacement activities (possible review and inclusion for Tree Safety Management Plan) Mains types LV ABC/XLPE LV bare/covered Existing HV ABC Urban non-bushfire prone areas Grow-in hazards only 22 For Official Use Only

23 What has changed and why? Risk Mitigations LV ABC/XLPE & HV ABC: Intermittent or sustained (but not permanent) contact No contact if greater than 25mm dia. ( thumb ) Low risk of entanglement Intact insulation LV bare/covered: Intermittent contact with foliage only Conductor spreaders Spans 50m Low risk of entanglement Regrowth allowance (but reduced below conductors) 23 For Official Use Only

24 What does this mean practically? Contractors will change cutting practices to comply with the changes to the urban profile in NS179. This includes a reduced clearance to LV conductors. 24 For Official Use Only

25 What does this mean practically? The changes will require consultation, training and guidance during the implementation stage. Maintain a close working relationship with Ausgrid s contract management officers and Ausgrid s arborists to determine the minimal vegetation removal to maximise electrical safety and reliability outcomes within the cutting cycle. Identification and recording significant limbs 25 For Official Use Only

26 What does this mean practically? Increased customer reported vegetation encroachments. Higher level of customer reported vegetation work. This will require further education and community interaction to describe the change in vegetation treatment led by the Network Standard. Working closer around the network. Defined work practices will help to minimise risk to the network and employees. Cutting of smaller vegetation resulting in many more hangers. Leads to potential debris being left after contractors leave site. 26 For Official Use Only

27 For Official Use Only