kaon fusesaver brochure - low res[1]

The most cost effective way of protecting medium voltage spur lines

Figure 1 Fuse Protected Spur Line Network

Figure 2 Unfused Spur Line Network

In most network configurations the primary feeder is protected by a circuit breaker or ACR (automatic circuit recloser) whilst the spur line is often protected by a fuse. When a fault occurs on the spur line, the ACR on the main feeder is coordinated such that the fuse will clear the faulted section. (fig.1)

The problem this approach causes utilities is that the fuse will blow on transient faults causing downstream users to be without power and incurring high costs on the utility to send a line crew to replace the fuse. The typical cost for a utility to find and replace a single fuse in Australia is estimated from $500 to $1,000. Up to 80% of blown fuses are caused by transient faults.

An alternative approach is to not protect the spur line. When a fault occurs on the spur line, the ACR on the main feeder will clear the transient fault. However in some cases the spur line fault level may be too low to allow this approach to work at all. (fig.2) The main problem with this approach is that ALL customers fed by the primary feeder experience a loss of supply due to a spur line fault. If the fault is permanent then a large number of customers will experience an extended period of no supply risking financial penalties to the utility for poor service levels. To improve network reliability and reduce operating costs a device that prevents the fuse from blowing on transient faults at a cost that justifies its use on spur lines is required. The Kaon FuseSaver fulfils this need!

The FuseSaver is a self powered, electronically controlled, single-phase fault interrupting device that works with a fuse to protect the spur line from both transient and permanent faults. The FuseSaver is capable of detecting, opening and clearing a fault in a half cycle which in most cases is less time than it takes for the fuse to melt. (fig.3) The key principle is that the fuse provides protection for the line whilst the FuseSaver protects the fuse from transient faults.

The Kaon FuseSaver offers the only cost effective solution to reduce the impact of transient faults on spur lines.

The main benefits of the FuseSaver are:• Transient faults do not cause upstream protection to operate• Transient faults do not cause the fuse to blow • Improves SAIDI and SAIFI for the utility• The protection grading of the network is unaffected by the addition of the FuseSaver • Self powered and self resetting• Simple line installation• Maintenance free - install and forget• Event Log to record line faults and lost customer minutes• Smart Grid enabled with Communication Module addition

Figure 3 FuseSaver operates on Transient Fault

Figure 5 Fuse Isolates Permanent Fault

CURRENT

OPEN

FUSESAVER CLOSED

OPEN

FUSE CLOSED

Transient Fault Load Current

CURRENT

OPEN

FUSESAVER CLOSED

OPEN

FUSE CLOSED

Permanent Fault

Figure 4 Operating Sequece: Transient Fault

Figure 6 Operating Sequence: Permanent Fault

| Ph: (07) 3209 5805 | PO Box 1187, Oxenford, QLD, 4210 | www.kaonelectric.com | 3

During installation the FuseSaver is set to match the current rating and type of the fuse. When operating, the FuseSaver performs an open, remains open for the prescribed dead time, then closes. After completing this open-close sequence the line must remain fault free for a minimum time before the FuseSaver will trip again on a fault. This results in the following performance under various circuit conditions…

When a transient fault occurs on a spur line the FuseSaver detects the overcurrent and opens in less time than it takes for the fuse to blow. It is held open for a fixed period of time to allow the fault to clear (dead time). The FuseSaver then automatically returns to the closed state reconnecting supply. If the fault has cleared, normal line current resumes and the fuse is unaffected. (fig.4) The benefit is that the customers on the spur line are the only ones affected by the fault and the interruption is temporary. The utility will not need to deploy a line crew to replace a blown fuse.

When the fault is permanent the FuseSaver opens, temporarily clears the fault and then closes, re-energising the faulted line. Since the fault is permanent the fault current resumes, the FuseSaver will now stay closed and allow the fuse to blow, dropout and isolate the line. (fig.5+6)

In this scenario the utility deploys the line crew to repair the permanent fault and to replace the fuse, (as was always necessary for a permanent line fault). The minimum number of customers will have experienced the effects of the fault.

Figure 7 Fuse Saver Internal Overview

Figure 8. Protection off lever operated

Dead-end

Vacuum Interrupter

Electronic Module

Magnetic ActuatorCurrent Transformer

Table 1: Fault Current limit by Fuse Rating and Type

Protection Lever Off

Indicator

The FuseSaver hangs directly from the MV line by clamping on the dead end and is an electrically floating device. It has no earth connection and therefore no permanent electrical stresses on its insulators. It is self powered by scavenging and storing energy from the spur line current. (fig.7)

Fault detection is achieved with a sense current transformer and a high speed protection algorithm. Fault interruption is achieved with a magnetic actuator operated vacuum interrupter.

For the FuseSaver concept to work it must be able to coordinate with a MV distribution expulsion fuse. The FuseSaver can detect, open and clear a fault in the first half cycle of current. This means the limit of coordination is when the fuse melts within a half cycle of current. This limit is a function of the fuse type and rating. The adjacent table shows the maximum fault current for a given type and rating of fuse where the FuseSaver can reliably save the fuse.

A key benefit of working with the existing fuse on the line is that the network protection grading does not need to be recalculated or changed! The FuseSaver is a fit and forget device protecting the existing fuse from transient faults.

For very high fault levels, despite the FuseSaver clearing the fault in a half cycle, enough energy is let through to melt the fuse. Most spur lines simply do not have fault levels this high.

The external lever when pulled down turns the protection off and the FuseSaver will not trip on a fault. Protection is re-armed when the lever is returned and latched in the up position. (fig.8)

An indicator of the OPEN/CLOSE contact status of the vacuum interrupter is visible through a transparent window from ground level.

Fuse Rating T Type K Type Boric Acid E Type

Boric AcidE Slow

6 350 220

10 650 400 450

15 1100 650 700 830

20 1400 850 900 1100

25 1900 1100 1200 1400

30 2400 1300 1400 1700

40 3000 1800 1800 2500

50 4000 2200 2100 3200


The FuseSaver scavenges energy directly from the MV line. This requires a minimum line current of 0.5A for the FuseSaver to turn on. When turned on, the FuseSaver charges up capacitors to operate the magnetic actuator. Until the capacitors are charged, the FuseSaver will not trip. The charging time is a function of the line current and must be completed before the protection is armed.

Table 2: Charging Time vs Line Current

Line Current Charging Time1.0 A 1800 sec5.0 A 180 sec

10.0 A 30 sec

With the addition of the Communications Module that has a battery, the recharge time reduces to 30 seconds.

The FuseSaver stores an event history in memory. Events are time stamped from the last power up of the FuseSaver. Typical events include:

• Line Current on/off• Protection Trip - records peak current and time from pickup to trip.• Close - records reason for close.• Transient Fault/Fuse Saved - the FuseSaver tripped on a fault, waited dead time, closed and found that line current is normal.• Permanent Fault - The FuseSaver tripped on a fault, waited dead time, closed and found that the line is de-energised.• Manual TRIP• Manual CLOSE• PROTECTION OFF set/reset

Functionality Un-Fused Fuse Drop out Sectionalizer

Kaon Electric

FuseSaver

Dropout Single Phase

Recloser

Single Phase Hydraulic Recloser

Transient fault does not require site visit to reconnect supply

No momentary outage on the main feeder for spur line faults

Isolate a permanently Faulted spur line

Visible point of isolation

Self Powered

Protection Grading is maintained

Operations Staff do not need re-training

Maintains Event History

Remote Control and Monitoring (1)

Low Installation Cost

Relative Purchase Price (3 phases) compared to FuseSaver 0% 20% 90% 180% 300%

(1) By addition of a communications module to provide remote control and line monitoring functionality.

From this comparison it is evident that the Kaon FuseSaver has superior performance at a lower cost for the effective protection of spur lines than any other solution on the market.

Table 3 below presents a comparison of the available options in the protection of spur lines.

Figure 9

Figure 10

Communications Module

FuseSaver and Communications Module

FuseSaver fitted with Communications Module

The Communications Module enables an operator to interface with the FuseSaver from ground level using a laptop computer loaded with the Kaon FuseSaver application Kaon Connect and fitted with the Kaon USB radio antenna.

The Communications Module contains a battery power supply and a short range (approx 15m) radio using a propriety protocol. It is inserted into the FuseSaver using a live-line stick fitted with the Kaon Communications Module attachment tool. The insertion is well guided and easy to execute with the Communications Module locking into the FuseSaver chassis. (fig.9+10)

A Communications Module must be attached to the FuseSaver for installation and commissioning purposes. Following commissioning it may be removed or may be left permanently attached to the FuseSaver to provide a range of enhanced functions.

To commission FuseSavers the communications module is attached and the Kaon FuseSaver PC application, Kaon Connect, is used to load the required settings into the FuseSaver memory via the radio link. Key data uploaded includes...

• Grouping a set of three FuseSavers to protect a three phase line• Naming of the site to uniquely identify the location and the power line• Fuse type and rating• The policy settings of the utility• Latitude and longitude (optional)

Loading settings is quick and simple and the user is guided through the process by Kaon Connect Configuration Tool. An LED on the underside of the communications module visible from ground level is used to confirm selection of each FuseSaver. Once configured the FuseSaver may be opened and closed as required for the commissioning purposes.(fig 11)

Figure 11

FuseSaver LED blink during commissioning

Manual trip/close levers


When Communications Modules are fitted to the FuseSaver it is possible to manually open and close the FuseSaver. This can be achieved by either using Kaon Connect or by operating the exposed trip or close levers on the underside of the Communications Module.

When multiple FuseSavers have been configured to operate as a group on a poly-phase line, then the tripping and closing will be executed synchronously via the inter-phase communications. As such, it is only necessary to depress the trip or close lever on one Communications Module and all FuseSavers will operate synchronously after a 30 second delay. The LED light on the underside of the Communications Module blinks to indicate the manual operation request has been initiated.

When in communication with the FuseSaver the Kaon Connect PC application displays status of the FuseSaver, phase currents and time/magnitude of the most recent fault (if known). (fig.12)

When the line is dead, the Communications Module supplies energy to the FuseSaver, so that...

• The time and date can be maintained even if the line current has been dead for a period of time. This means that events have improved time stamping.• The inhibit time can be kept to the minimum as the recharge energy is supplied by the batteries in the Communications Module and is not dependent on line current. This will give improved performance during storms when frequent transient faults may occur in a short period of time.

Figure 12 Kaon Connect - FuseSaver Status Page

While the Kaon Connect PC application is connected to the FuseSaver via the Communications Module it is possible to download the event log from the FuseSaver memory and view it on the PC. In addition, Kaon Connect can calculate the duration of lost supply and number of interruptions to supply to provide reliability metrics for the line it is protecting.

With Communications Modules permanently deployed on FuseSavers they are enabled to interface with the Kaon Remote Control unit (KRC) (due for release in 2011). The KRC will communicate via the short range radio on the Communications Module with the FuseSavers and by long range radio or other medium as part of the utility’s SCADA System.

This will allow the utility to remotely monitor and control the FuseSavers including receiving of alerts of faults and loss of supply.

Ratings Value ValueRated maximum voltage 12kV 24kVFuse ratings up to 50A

Rated indefinite overload current 100AFault break capacity 4kA RMS / 10kA Peak100 % fault break operations 10 30Minimum tripping current x 2 Fuse rating (Configurable)Mechanical Operations Endurance 2,000Rated Frequency 50 HzMinimum line current for operation 0.5 AWeight 5.3 kgs

The Kaon Electric FuseSaver has been extensively tested, to ensure a long life and reliable performance.

Tests OverviewInterruption Duty Short circuit breaking tests at 12kV, 1kA, 3kA and 4kA that

comply with the expulsion fuse standard AS 1033.1 and IEC60282-2

Line Charging Interruption tests at 12kV, 1A in accordance with IEC 60265-1Transformer Magnetising Current

Interruption tests at 12kV 3.3A transformer magnetising current.

Temperature Rise 100A Temperature rise as per IEC 60694 and AS 2650Degree of Protection

IP rating of IP57

Mechanical Duty 2000 operations

Arc Fault Arc fault test at 12kV, 3 kA and 250ms. There were no emissions of arc products from the FuseSaver.

EMC Transient burst withstand tests, lightning impulse tests and ESD tests conducted on FuseSaver electronics.

Parameter ValueMaximum Operating Ambient Temperature +500CMinimum Operating Ambient Temperature -400CSolar Radiation 1.1 kW/m2Maximum altitude 3,000 mHumidity 0 to 100%

The FuseSaver has the following ratings…

The FuseSaver has been designed for the following environmental extremes…

Figure13 Direct Line Mounted

Figure14 Cross Arm Method


There are two methods that the FuseSaver can be mounted in service. It can be supported directly from the MV line or it can be mounted on a stand-off insulator on a cross arm. The FuseSaver is designed to be mounted horizontally in all configurations.

When hanging the FuseSaver directly from the MV line the FuseSaver Terminal Line Clamp must be fitted. This terminal clamp attaches to the dead-end of the MV line and ensures that the FuseSaver is hung at its centre of mass (5.3 kgs). The clamping to the dead end provides a solid mechanical mounting point and is not a conducting joint. A connection cable is run from the conducting line to a connection point on the terminal clamp.

The terminal clamp provides clearance between the live line and the output terminal when the FuseSaver is in the open state. (fig 13)

For the free end of the FuseSaver a number of connection methods are available for the dropper that connects to the fuse. • Single hole palm• Nema two hole palm

It is recommended that a bird guard is fitted to the exposed free end.

For installations where mounting directly on the line is not practical the FuseSaver can be mounted from a cross-arm using the Kaon cross-arm mounting assembly. This consists of a station post insulator with custom end fittings that connect to the FuseSaver and to the cross-arm. The FuseSaver is mounted from the two end lugs and can withstand a cantilever load of 100kgs applied at any position along the length of the FuseSaver body. (fig.14)

Connecting CableDead End

Line Clamping Assembly

FuseSaver Mounting

Crossarm Clamp

Station Post Insulator

Figure15 Line Clamping Assembly

Figure16 Cross-Arm Mounting Assembly

Figure17 Bird Guards

Figure18 USB Radio Antenna

A range of accessories are available for the FuseSaver that provide mounting and communications options.

COMMUNICATIONS MODULE ATTACHMENT TOOLThe Communications Module attachment tool is fitted to a live-line stick via the sun-rise connection. It allows Communications Modules to be safely installed and removed from the FuseSaver.

LINE CLAMPING ASSEMBLYThe line clamping assembly provides both the mechanical mounting of the FuseSaver from the dead-end of the overhead line and also provides a separate electrical connection. The clamping assembly is manufactured from marine grade aluminium and uses stainless steel fasteners to ensure long performance even in coastal or polluted environments. (fig.15)

CROSS-ARM MOUNTING ASSEMBLYThe cross-arm mounting assembly is an accessory only available from Kaon Electric. The stand-off insulator is manufactured from porcelain and is available in different lengths to match the BIL required up to 150kV. The cross-arm end provides a universal attachment point for all cross-arm cross-sections and can accept bolt sixes up to M20. (fig.16)

BIRD GUARDSBird Guards are available for the free end of the FuseSaver. (fig 17)

PC COMMUNICATIONS KITThe PC Communications Kit includes a CD with the Kaon Connect PC application and a USB Radio Antenna to enable radio communications between the laptop and the FuseSaver Communications Module.

COMMUNICATIONS MODULE CARRY CASE KITThe Communications Carry Case Kit is a heavy duty case that contains all the items necessary for a line crew to communicate with base FuseSavers.

It includes...• 3 x Communications Modules• 1 x Communications Module Attachment Tool• 1 x PC Communications kit


Use the check sheet to fully configure your order. Please use the section “special requirements” to let us know how we can further configure your order to meet your exact needs..

ORDER CODE Description Qty

KFS-12-4-100 FuseSaver - 12kV - 4kA - 100A

KFS-24-4-100 FuseSaver - 24kV - 4kA - 100A

KFS-CM-TCB Communications Module

KFS-CM-AT Communications Module Attachment Tool

KFS-CM-PC 1PC Communications kit

KFS-CM-CCK

Communications Module Carry Case Kit- 2 x Communications Module - Basic - 1 x Communications Module - TCB - 1 x Communications Module Attachment Tool- 1 x PC Communications Kit

KFS-5018 FuseSaver Line Clamping Assembly

KFS-5023 24kV - 150kV Cross-Arm Mounting Assembly

KFS-5024 12kV - 110kV Cross-Arm Mounting Assembly

KFS-1123 KFS Bird Guard - Vertical Tail

SPECIAL REQUIREMENTS

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KAON ELECTRIC

Kaon Electric is based in Brisbane, Australia. The Kaon Electric team have been designing and manufacturing pole mounted electrical

switchgear for the past 20 years and are collectively responsible for some of the most innovative products on the market today.

Kaon Electric is focused on developing products that address the changing world of electricity distribution. Every product developed

by Kaon Electric provides a new level of functionality not found in other products.

Ph: (07) 3209 5805 [email protected].

37 Chetwynd St, Loganholme, QLD, 4127PO Box 1187, Oxenford, QLD, 4210

Kaon Electric Pty Ltd applies a policy of continuing product development and reserves the right to change the design and/or specification of this product without notice.

Kaon Electric Pty Ltd does not accept any responsibility for any loss or damage incurred by anyone as a result of information published in this guide.

kaon fusesaver brochure - low res[1]

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