Introduction

The OSM Ground Mount Kiosk is designed for the connection and protection of underground cables for voltage classes up to 38kV.

The kiosk houses an OSM automatic circuit recloser, an RC10 controller, an interlocked isolation and earthing mechanism, and cable connection compartment.

The OSM automatic circuit recloser has been extensively type tested by independent laboratories to ensure long life and reliability under the harshest environmental conditions. It is the only solid di-electric insulated recloser to provide controlled arc fault venting and independent testing provides verification of this important safety feature.

The RC10 controller provides all the protection, data logging and communications functions. An operator panel is used to operate the device locally.

A two phase VT located in the main compartment provides low voltage AC auxiliary supply to the RC10 controller.

A manual trip mechanism is located above the RC10 controller, and is used to manually open and isolate the OSM. The mechanism is then rotated using a lever to connect earth switches to the Load side of the OSM.

Underground cables enter the kiosk through a metal plate provided in the base of the cable connection compartment. 6 DIN 400 Taper or ANSI taper aromatic epoxy bushings are provided to terminate the cables onto the Load and Source side of the OSM automatic circuit recloser. An earth bar is also located in this compartment for earth bond connections.

The kiosk is manufactured from zinc anneal and is powder coated. The control compartment is protected to IP 65, while the main compartment and cable connection compartment are both protected to Ip55.

The kiosk is mounted on a hot-dip galvanised plinth base. Two lifting points are provided on the top of the kiosk at either end. The plinth has two sling guides underneath so the kiosk can be lifted in a safe manner.

 

Overview

The OSM automatic circuit reclosers incorporate vacuum interrupters inside a polycarbonate housing enclosed inside an arc vented stainless steel tank. This ensures the maximum in life and reliability with a fully insulated arrangement inside the long life housing.

Voltage is measured on all six (6) bushings using capacitively coupled screens. Current is measured on all three (3) phases using current transformers.

The recloser mechanism is operated by three (3) separate magnetic actuators, one per phase. These magnetic actuators are mechanically interlocked to guarantee correct three (3) phase operation. The device is latched in the closed position by magnetic latching. Each magnetic actuator uses a single coil.

The open and closed position of the device is indicated by a green '0' to indicate the device is open and a red 'I' to indicate the device is closed, this can be viewed through the window next to the control cubicle.

The status of the recloser is also reflected by a microswitch connected to the control electronics. The electronic circuit board where the microswitch is fitted has no active elements which dramatically improves impulse immunity.

The main circuit bushings are manufactured from UV stable polymer and have a silicone rubber bushing boot to provide the required creepage distance.

The magnetic actuators are operated from stored energy charged capacitors located in the RC control cubicle. There is a rating plate located in the base of the tank that provides tank rating details in accordance with the requirements of ANSI C37.60.

The cross sectional diagram below details the OSM tank configuration and main components.

Electronic Controls

The RC10 control and communications cubicle is a microprocessor based controller that provides a directional overcurrent, earth fault and sensitive earth fault relay, auto reclosing relay, instantaneous metering, event log, demand logger and remote terminal unit (RTU) for remote control in a single package.

The operator control panel is provided with a large backlit LCD display and keypad to provide local control functions.

Protection

• 4 Independent Protection Groups
• Directional over current and earth fault protection
• Inverse Time Protection
• Definite Time Protection
• High set Instantaneous element
• Directional Sensitive Earth Fault Protection
• Under and Over Voltage Protection Element
• Under and Over Frequency Protection Element
• Zone Sequence Co-ordination
• Voltage reclose control with automatic back feed restoration provides loop automation functionality.
• Live Line Function & Hot Line Tag Function

Specification

Part Number	OSM15-16-630	OSM27-12-630	OSM38-12-630
Current Sensing	3 x Current Transformers	3 x Current Transformers	3 x Current Transformers
Voltage Sensing	6 x Voltage Screens	6 x Voltage Screens	6 x Voltage Screens
Control Type	RC 01ES	RC 01ES	RC
Rated Maximum Voltage	15.5kV	27kV	38kV
Rated Continuous Current	630A	630A	630A
Fault Make Capacity RMS	16kA	12.5kA	12.5kA
Fault Make Capacity Peak	40kA	31.5kA	31.5kA
Fault Break Capacity	16kA	12.5kA	12.5kA
Mechanical Operations	30,000	30,000	30,000
Full Load Operations	30,000	30,000	30,000
Fault Break Capacity Operations	200	200	200
Short Time Current Withstand	16kA/4 secs	12.5kA/4 secs	12.5kA/3 secs
Mainly Active Breaking Capacity	630A	630A	630A
Cable Charging Current	25A	25A	40A
Line Charging Current	10A	5A	5A
Impulse Withstand Phase to Earth & Phase to Phase	110kV	125kV (150kV option)	170kV
Impulse Across the Interrupter	110kV	125kV (150kV option)	170kV
Power Frequency Withstand Phase to Earth (Dry)	50kV	60kV	70kV
Across the Interrupter	50kV	60kV	70kV
Ambient Temperature	-40°C to +55°C	-40°C to +55°C	-40°C to +55°C
Humidity	0-100%	0-100%	0-100%
Altitude	3000M	3000M	3000M
Weight of the Tank	720kg	720kg	775kg