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25 Years Gas-Insulated Medium-Voltage Switchgear from Siemens Resistance to Internal Faults Martin Schaak Olaf Bischur Thomas Stommel.

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Presentation on theme: "25 Years Gas-Insulated Medium-Voltage Switchgear from Siemens Resistance to Internal Faults Martin Schaak Olaf Bischur Thomas Stommel."— Presentation transcript:

1 25 Years Gas-Insulated Medium-Voltage Switchgear from Siemens Resistance to Internal Faults Martin Schaak Olaf Bischur Thomas Stommel

2 Power Transmission and Distribution © Siemens AG 2006 Page 2 June 07 Medium Voltage Division Topics Resistance to internal faults Causes and physical effects Basic standard IEC Test object NXPLUS C Live test Analysis and review Open questions

3 Power Transmission and Distribution © Siemens AG 2006 Page 3 June 07 Medium Voltage Division Causes of Internal Faults Ageing of insulating materials under electrical stress Corrosion Overstressing Ferroresonance, overvoltages Defective installation, incorrect maintenance Maloperation Pollution, humidity, small animals penetrating in the switchgear

4 Power Transmission and Distribution © Siemens AG 2006 Page 4 June 07 Medium Voltage Division Electrical Accidents 1 internal arcing fault per 10,000 GIS panels and year Reported electrical accidents in the sphere of activity of BGFE 49.3% Electric shock 27.0% 20.8% 5.8% 1.5% 27.4% 47.1% Arcing faultElectric shock and arcing fault Arcing fault with electro-ophthalmia and burns 67.5 % 80 % 0 % 20 % 40 % 60 % Electrical effects of high voltage Institute for the research of electrical accidents

5 Power Transmission and Distribution © Siemens AG 2006 Page 5 June 07 Medium Voltage Division Physical Effects of an Internal Fault Temperature rise and pressure rise Radiation EvaporationThermal conduction, melting Electric arc, plasma beam with a temperature of about 20,000 °C Energy balance

6 Power Transmission and Distribution © Siemens AG 2006 Page 6 June 07 Medium Voltage Division Possible Effects of an Internal Fault Light effect (blinding, shock) Noise development (hearing damage) Thermal load (heat, burns) Smoke development (breathing) Projection of parts (cuts) Toxic effects (intoxication) Pressure development (damage to buildings / walls and door), physiological influence on a person (shock, falling caused by defensive reaction, circulatory insufficiency)

7 Power Transmission and Distribution © Siemens AG 2006 Page 7 June 07 Medium Voltage Division Avoidance of Internal Faults Quality during design, production and installation Training of personnel (avoidance of maloperation) Maintenance (replacement of worn-out parts, cleaning) Active systems for fault detection Other measures for avoidance of internal arcs are described in IEC , Table 2: Locations, causes and examples of measures to reduce the probability of internal faults

8 Power Transmission and Distribution © Siemens AG 2006 Page 8 June 07 Medium Voltage Division Comparison of the Internal Arcing Test IEC vs. IEC Test conditions according to IEC 60298Test conditions according to IEC Application of test conditions by agreement between manufacturer and operator Test according to defined conditions of the standard Any room height, distancesDefined test setup, distances Any points for arc initiationDefined points for arc initiation Defined acceptance criteria can be appliedDefined acceptance criteria must be applied Feeding directions freely selectableDefined feeding direction Declaration on rating plate not necessary Internal arc classification (IAC) must be declared on the rating plate Description of test resultsTest passed / not passed

9 Power Transmission and Distribution © Siemens AG 2006 Page 9 June 07 Medium Voltage Division Classification with IAC Tested and passed according to standard conditions Classification without IAC Not tested or not passed Existing switchgear assemblies tested to IEC are still allowed to operate, however they might not be comparable with other switchgear. Consequence for operators (as comparisons are hardly possible) Request tests according to the prescribed general standard, i.e. IEC This provides the quality feature of standardized comparability. Comparison of the Internal Arcing Test Consequences from IEC

10 Power Transmission and Distribution © Siemens AG 2006 Page 10 June 07 Medium Voltage Division Designation of the Internal Arc Classification *F = Front; L = Lateral; R = Rear Classification:IAC ( Internal Arc Classified ) Accessibility:A (F, L, R)* B (F, L, R)* C Test values:Current [ kA ] and duration [ s ] Example 1:IACAFLR25 kA1 s Example 2:IACBFL25 kA1 s

11 Power Transmission and Distribution © Siemens AG 2006 Page 11 June 07 Medium Voltage Division Test Procedure Busbar compartment Circuit-breaker compartment Cable compartment For switchgears with internal arc classification (IAC) according to IEC : Test object consists of 2 panels as a minimum Test in every compartment and at least in the end panel Completely equipped test specimen (reproductions are accepted) Test only on not pre-stressed functional compartments Defined distances (walls, ceiling) 40 % to 50 % of the surface must be covered with indicators Defined direction of power flow and points of arc initiation SF 6 -insulation may be replaced by air Evaluation of all five criteria

12 Power Transmission and Distribution © Siemens AG 2006 Page 12 June 07 Medium Voltage Division Test Arrangement Conditions (1) (a) Height of ceiling - Height of test object mm ± 100 mm - If height of test object 1.5 m > Min. height of ceiling 2 m (b)Rear wall - Non-accessible 100 mm ± 30 mm - Accessible 800 mm mm (c)Indicators - Covering 40 to 50 % (checker pattern) 800 mm 100 mm 600 mm

13 Power Transmission and Distribution © Siemens AG 2006 Page 13 June 07 Medium Voltage Division Test Arrangement Conditions (2) For the test object in the room mock-up For the indicators

14 Power Transmission and Distribution © Siemens AG 2006 Page 14 June 07 Medium Voltage Division Acceptance criteria Criteria according to IEC No. 1 Correctly secured doors an covers do not open Deformations are accepted with restrictions Additionally, if distance to wall after installation is smaller than tested: The permanent deformation is less than the intended distance to the wall No. 2 No fragmentation of the enclosure No projection of parts above 60 g No. 3Arcing does not cause holes in the accessible sides up to a height of 2 m No. 4Indicators do not ignite due to the effect of hot gases No. 5The enclosure remains connected to its earthing point new

15 Power Transmission and Distribution © Siemens AG 2006 Page 15 June 07 Medium Voltage Division Test Setup Current test object, open vessel and ignition wire

16 Power Transmission and Distribution © Siemens AG 2006 Page 16 June 07 Medium Voltage Division Test Parameters Type of accessibility A Free-standing arrangement Short-circuit current: 25 kA Short-circuit duration: 1 s Height of ceiling: 2.8 m Switch position of all devices: CLOSED Operating tool inserted Infeed via right-hand disconnector panel 3-phase arc initiation in gas vessel of CB-panel at cable connection bushings Direction of power flow as feeder panel IAC A FLR 25 kA 1 s

17 Power Transmission and Distribution © Siemens AG 2006 Page 17 June 07 Medium Voltage Division High-Power Test Laboratory at the Location Frankfurt am Main

18 Power Transmission and Distribution © Siemens AG 2006 Page 18 June 07 Medium Voltage Division Test Preparations Arrangement of test object in room mock-up

19 Power Transmission and Distribution © Siemens AG 2006 Page 19 June 07 Medium Voltage Division Live Test Performance of internal arcing test (Changeover to high-power testing laboratory)

20 Power Transmission and Distribution © Siemens AG 2006 Page 20 June 07 Medium Voltage Division Flashback (Slow Motion of Live Test) Test recorded from different camera positions Camera A Camera B Camera C Switchgear front Switchgear side

21 Power Transmission and Distribution © Siemens AG 2006 Page 21 June 07 Medium Voltage Division Acceptance Criteria Criteria according to IEC No. 1Correctly secured doors and covers did not open. No. 2 No fragmentation of the enclosure occurred and no parts with an individual mass > 60 g were projected. No. 3Arcing did not cause holes in the accessible sides of the enclosure up to a height of 2 m. No. 4No indicators ignited due to the effect of hot gases. No. 5The enclosure remained connected to its earthing point.

22 Power Transmission and Distribution © Siemens AG 2006 Page 22 June 07 Medium Voltage Division Resulting Document As an example from previous tests

23 Power Transmission and Distribution © Siemens AG 2006 Page 23 June 07 Medium Voltage Division Discussion / Questions Testing Laboratory Medium Voltage Frankfurt am Main Your competent partner for tests on medium-voltage switchgear

24 25 Years Gas-Insulated Medium-Voltage Switchgear from Siemens Thank you very much for your attention!


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