HV Power

Customer Newsletter - April 2025

DIGSI 4. Use 4.95 (Especially with SIPROTEC 4 Compact 7SJ80 and 7SD80

While DIGSI 4 v4.96 has been released and we normally recommend using the latest, in this rare case we recommend that customers keep using v4.95 when working with SIPROTEC 4 and SIPROTEC 4 Compact relays.

v4.96 was released to support a new variant of the 7SJ64 relay. Unfortunately, it also introduced a bug that does not allow v4.96 to connect via USB interface to SIPROTEC 4 Compact relays (e.g. 7SJ80 and 7SD80 series relays). These Compact relays are popular with our NZ utility and infrastructure customers.

HV Power and Siemens Australia therefore recommend that SIPROTEC 4 designs and connections to relays are done with DIGSI 4.95. There is no critical need in New Zealand to upgrade to 4.96 (as that 7SJ64 variant is not used here).

Please use 4.95

As a reminder with the phase-out of SIPROTEC 4, at this time there are ‘like’ replacements for all products, except the Compact 7SD80 series which will be addressed by the end of this year.

WRNO - Week Number Roll Over - Tekron GPS Clocks

GPS satellite signals don't transmit the year, but rather the number of weeks since EPOCH (the date the GPS system went live). Your clock calculates the year from that number. As a three-digit counter was used, every 19.5 years this counter ‘rolls over’ from 999 back to 000. Therefore older GPS clocks could jump back 19.5 years. Manufacturers now add WNRO counters and other solutions to detect a roll over to still show the correct year. Some of these solutions eliminate the WNRO or postpone it to being 19.5 years from the clock firmware date.

With the change of daylight saving having just occurred, now is the time to give your clocks a close check. For Tekron clocks it's likely to be those running GPS Receiver firmware d1.05 to d1.07. You need to log onto the clock to see this, but typically if your clock was supplied between February 2019 and December 2022 then it's worth checking the GPS Receiver firmware version and being aware of this potential. There is a risk in doing this upgrade so we do not recommend a pre-emptive upgrade, but rather being aware of what needs doing should a WNRO occur.

8DA10 is now supplied via HV Power

As part of the growing relationship between HV Power and Siemens and our highly regarded VAR status, we (rather than Siemens) are now supplying Siemens 8DA10 to the New Zealand market. We recently had our first panels through our workshop for local LV control panel wiring and customisation.

See our website Switchgear product section below for more information on 8DA10

HV Power Switchgear

Siemens NXAIR Medium-Voltage Switchgear

While much of our focus is on gas-insulated switchgear, here is a reminder that HV Power and Siemens are also in the air-insulated switchgear business. We have recently been working on customising a NXAIR panel and its withdrawal breaker unit.

Siemens NXAIR is a state-of-the-art air-insulated switchgear (AIS) system designed for medium-voltage indoor applications up to 24 kV. Engineered for performance and durability, NXAIR offers high operational safety, low maintenance, and easy integration into various industrial and infrastructure applications. NXAIR offers a modular, metal-enclosed, and metal-clad design in accordance with IEC 62271-200 standards to ensure both personnel and operational protection.

Key Technical Features:

• Rated Voltage: Up to 24 kV

• Rated Current: Up to 4000 A

• Short-Circuit Withstand Current: Up to 40 kA

• Type of Protection: Internal arc classification IAC AFL up to 40 kA, 1s

• Design Standards: IEC 62271-200, LSC 2B, PM

• Busbar System: Horizontal, extensible, single or double busbar options

• Vacuum Circuit Breaker: Maintenance-free for up to 30,000 operations

• Installation: Front access for operation, cable connection, and maintenance – ideal for space-constrained environments

With its modular construction and flexibility, NXAIR can be tailored to meet specific application needs in industries such as power generation, utilities, oil & gas, transportation, and commercial infrastructure.

See our website Switchgear product section for more information

HV Power Switchgear

Training

Our website lists all of our 2025 Auckland-based training courses. Please check the topics and dates.

Get in quick as the next two courses are not too far away:

· Busbar Protection Relay Testing: 21 May 2025

· Process Bus Applications: 4 Jun 2025

The HV Power website training page has more details about these courses and all our other training courses for 2025.

For more information on any items in this newsletter contact HV Power via sales@hvpowerautomation.com, phone +64 9 377 2001 or via our web form at www.hvpower.co.nz