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  MORE than a supplier     HV Power Customer Newsletter September 2016    
           
        KIWI REPORTER - Fault Passage Indicator SCADA interface    
 

    In this issue:

Photo - Warwick Beech

 Commentary

Warwick Beech

Committed to RMUs!

The strong interest in our Siemens 8DJH Series of Ring Main Units has accelerated our learning of several different automation configurations, indoor switchboard applications, outdoor ‘Class B’ enclosure (the Bosecker enclosure) and outdoor Class A enclosures.

Since taking our demo RMUs to most utilities (a few times!) we’ve now further demonstrated our full commitment to offering a quality RMU range in NZ by completing Installer Training with one utility that has accepted the 8DJH on their network.

Our commitment to customers is to deliver price-competitive and credible (if not superior) alternative switchgear to the NZ market. Our focus goes way beyond delivering the Ring Main Unit into your store. We work with your supply and installation chain to help lower the overall cost of installation and, for some networks, we help put processes in place that can drive the catchup to replace older obsolete (and often defective) equipment.

While the emphasis has been on 11/22 kV 8DJH series switchgear and enclosure options, please note our newsletter article covering the 36 kV version, which now features circuit breaker options. This offers a credible option for cost-effective outdoor-to-indoor 33 kV conversions.

Regards

Warwick Beech

   
KIWI REPORTER

The first of our KIWI REPORTER’s has rolled off the production line. This is a variation and adaptation of the SMART REPORTER which is used to provide DNP SCADA connectivity to Horstmann overhead line mounted SMART NAVIGATOR Fault Passage Indicators.

The KIWI REPORTER features a large power supply and battery capacity to support high-power radios, like the 4RF Aprisa SR series. (The SMART REPORTER is designed for low-power GPRS/GSM modem communications.)

We have built the KIWI REPORTER using a stainless steel enclosure to provide long life for those utilities located in NZ’s harsher coastal environments. Contact us for more details on our AC and Solar-powered versions of the KIWI REPORTER or any Horstmann FPI product.

 

   
      IPEC Partial Discharge Testing    
     

To assist with the introduction of the IPEC range of Partial Discharge (PD) testing equipment in New Zealand and Australia, HV Power will be making customer presentations (Sept/Oct) supported by a factory expert. Watch out for details to your inbox soon.

Partial discharge is generally accepted as the predominant cause of long term degradation and eventual failure of electrical insulation. As a result, its measurement is common practice in factory testing of many types of high voltage equipment, and, many utilities now undertake an annual PD survey of installed equipment. However, with the latest generation of technology, PD monitoring products are now sufficiently cost effective and reliable (in the sense of not giving false warnings) to be permanently installed – without the need to have a 'guru' in your organisation decoding the resulting data. Permanently-installed devices are ideal for older switchgear, where periodic inspection may be too infrequent.

What is Partial Discharge?

Partial Discharge (PD) is an electrical discharge that does not completely bridge the space between two conducting electrodes. The discharge may be in, for example, a gas-filled void in a solid insulating material, in a gas bubble in a liquid insulator, or around an electrode in a gas.

Partial Discharge occurs at normal working voltages as the defects or cavities in solid insulation are usually filled with a gas of significantly lower breakdown strength than the surrounding material. In addition to this, the permittivity of the gas is invariably lower than that of the solid insulation, causing the electric field intensity in the cavity to be higher than that in the surrounding dielectric. Therefore, under the normal working stress of the insulation, the voltage across the cavity may exceed the breakdown value and initiate electrical breakdown, or ‘partial discharge’ in the void.

How do PD monitors work?

A combination of methods are best used, dependent upon the application:

  • Ultrasonic sensors are generally used to detect insulator surface tracking, where, for example, deposits on the surface over time cause tracking (PD). Tracking/corona generates a characteristic signature in its ultrasonic emission.
  • Transient Earth Voltage (TEV) sensors are used to measure internal PD in the equipment. They achieve this as the partial discharge induces small voltage impulses (called TEVs) on the surface of the metal switchgear. The TEV sensor is capacitively coupled to the switchgear.
IPEC combine these detection methods with sophisticated noise detection algorithms - distinguishing between noise and PD - to help avoid false positive results. 

 

IPEC PD AlarmIPEC Ultrasonic sensor
IPEC’s PD Alarm Switchgear PD Monitoring System and Ultrasonic sensor.

See our website for more details, or contact us.

 

 

   
      Siemens 8DJH-36: 36 kV Ring Main Units – now with Circuit Breakers    
     

The popular 8DJH series of 11/22 kV switchgear has a bigger brother – the 8DJH-36. This range of switchgear is physically a slightly larger, scaled up version of the very successful 8DJH RMU's. In terms of front panel design and operation, it’s hard to tell the difference thus, saving the need for further operator training.

The 8DJH-36 is 36 kV rated (20 kA 3 sec) with a bus current rating of 630 A. The range includes:

  • Ring switches
  • Cable to bus panels
  • Transformer fused T-offs
  • Circuit breakers
  • Air insulated billing/metering panels (with option for cable connection left, right or both)

Suitable for indoor applications such as power distribution systems, energy supply of airports, railway stations, stadiums, and large industrial sites, the range includes several predefined, lower cost, single SF6 gas block configurations. It also possesses versatility with the option to allow future extensions of panels to left or right.

 

Siemens 8DJH-36 36 kV RMU
Siemens 8DJH-36 RIng Main Unit for 33 kV applications.

See the 8DJH-36 website to download the latest 8DJH-36 Catalogue.

 

   
Copyright 2016 HV Power Measurements and Protection Ltd