Tools

The following tools are available.

Disclaimer The information contained in the worksheets below has been compiled by the NZCCPTS for the use of its members from sources believed to be reliable, but neither the NZCCPTS nor any of the contributors to these worksheets (whether or not employed by NZCCPTS) undertake any responsibility for any mis-statement of information or mistake in the worksheets, and readers should rely on their own judgement or, if in doubt, seek expert advice on the application of the worksheets to work being carried out.

Calculation Worksheets

Worksheets are attached for calculating in Power Company Distribution Networks:

1. the EPR on distribution transformer earthing systems, HV conductive poles and urban MEN systems, and
2. the earth impedances of typical Urban MEN systems.

These worksheets correspond to worked examples used in the AS/NZS Handbook HB 219 ‘Earth potential rise – Protection of telecommunications users, personnel and plant – Worked examples for the application guide’.

EPR Calculation Worksheets

Earthing System EPR is Calculated for	HV voltage	HV supply	NER at HV source	Typical of which country	HB 219 Worked Example No.	Download PDF file	Download Mathcad file	Download Excel file
Rural distribution transformer	11 kV	Overhead	None	NZ	3.2.1
	22 kV	Overhead	None	Australia	3.2.2
HV concrete pole	11 kV	Overhead	None	NZ & Australia	3.3.1
	11 kV	Overhead	4 ohms	Australia	3.3.2
	22 kV	Overhead	8 ohms	Australia	3.3.3
	33 kV	Overhead	None	NZ & Australia	3.4.1
	33 kV	Overhead	20 ohms	NZ & Australia	3.4.2
Isolated 48 customer urban MEN system	11 kV	Overhead	None	NZ	3.5.1
Extensive interconnected urban MEN system	11 kV	Overhead	None	NZ	3.6.1
	11 kV	Overhead	20 ohms	Australia	3.6.2
	22 kV	Overhead	None	Australia	3.6.3
	22 kV	Overhead	8 ohms	Australia	3.6.4
	11 kV	Buried	None	NZ	3.7.1

Urban MEN Impedance Calculation Worksheets

Type of URBAN MEN network	Poles conductive and bonded to LV MEN	Typical of which country	MEN impedance value used in HB 219 Worked Example Nos.	HB 219 Worked Example No.	Download PDF file	Download Mathcad file	Download Excel file
Extensive interconnected MEN	None	NZ	3.6.1 3.7.1	4.1.1
	All	Australia	3.6.2 3.6.3 3.6.4	4.1.2
Isolated, 48 customer MEN	None	NZ	3.5.1	4.2.1

Mathcad Worksheets Version Number

The above Mathcad worksheets can be read using Mathcad version 10 (also known as Mathcad version 2001 or 2001i) or a later version of Mathcad.

To obtain a copy of Mathcad, or to get advice if you are having problems using Mathcad, visit www.ptc.com.