Specification for Lightning Sensor

Transcription

1 Specification for Lightning Sensor Patent Pending November

2 Content: 1. General description 2. Functional description 3. Electrical connections. 4. Electrical specifications. 5. Mechanical specifications. 6. Norms and standards. 7. Maintenance.

3 1. General description. At lightning strikes directly into the tower, where the lightning sensor is mounted, an immediate relay signal activates, telling that a strike has just taken place. At direct strikes in the neighbourhood of the tower, no indication will take place. Additionally no indication will happen at disturbances in the power supply circuit to the sensor. The lightning sensor detects as well weak as very strong strikes. By failures in the power supply (power-failure), the lightning sensor will continue to register lightning strikes and keep that information until full power supply is re-established and a relay signal is send out. The power supply is supervised electronically and by errors a relay signal is send out. Antenna Converterbox Antenna Optical fibre Controlbox + - Power Power failure Reset Lightning

4 2. Functional description Building blocks: The lightning strike will be detected by antennas that are smaller than a A4 piece of paper. The signals from the antennas are transformed from an electrical signal to an optical signal, which is transferred via an optical fibre to a control box, which may be placed in the turbine control rack. A complete galvanic isolation is by then obtained between the antenna and the control box. The relay output from the control box tells that there has been a lightning strike and it tells just immediately after the strike. The control box shows the lightning signal until the turbine control has send an acknowledge by sending a reset signal. Function: After signalling through the optical fibre a zero potential contact is switched on as an indication of a lightning strike. It is possible by internal jumpers to bring the output normal open or normal closed. At the normal closed setting a signal will also occur by cable failures. A drop of power supply will signal on the Power relay. This relay can also be set as normal open or normal closed. The Power Failure Relay signals at power drop out from the external supply. It also signals in case of failure from the internal lithium battery. The lightning sensor detects strikes even without the presence of external power supply. The battery lifetime is approx.1 month. At the reestablishment of the external power supply, the lightning relay will indicate strike, if there was a strike before the power was re-established. Then detection will also take place if the lightning sensor is not supplied by external power, as an example if the turbine is in a repair period. The lightning relay will only be reset after an active reset signal coming from outside. This reset signal must be of 5-10 sec. Of endurance. This lowers the risk of a reset just by electrical noise. The reset signal can be either an AC or DC signal in region 5-24V. The reset circuit is overvoltage protected and optical isolated from the rest of the control box circuit. On the control box a red LED shows the lightning detection. A green LED indicates external power supply. A red LED shows output from power failure circuit (only active if external supply is present) The external supply is protected against even high noise levels and other disturbances from outside.

5 3. Electrical connections. The control box cable is connected to the control box by the accommodating connector (Type C 091 D, IEC130-9, IP67): Connector seen from soldering end. A cable with screen must be used. Preferred external diameter is 6-7 mm. The connector has these connections: Pin 1 and 2: Power-failure relay Pin 3 and 6: Reset off lightning relay (pin 3 = negative at DC) Pin 4 and 5: Lightning relay 230V supply The 230V supply is connected via a IEC connector. The supply must have maximum 10Amp fuse.

6 4. Electrical specifications. Detection level: Lightning current from approx. 500A to approx A may be detected (8/20-8/350uSec). The trigger level is adjustable in the antenna box. The trigger level is adjustable to specific levels: 1kA, 2kA, 4kA or 8kA, resolution +/- 10% on table values. These values are depending on the distance between the antennas. The values are finally calculated in a table. Adjustment of the trigger level is done by change of connections inside the antenna box. The trigger current is filtered as a first order band-pass filter, having a specific characteristic. please ask Jomitek for more details. For a tower having a radius of 2,2 meters, the sensitivity is: Lightning Sensor Sensitivity 12,0 11,0 10,0 9,0 8,0 ka 7,0 6,0 5,0 4,0 3,0 2,0 1,0 0,0 0, kA adjust. 2kA adjust. 4kA adjust. 8kA adjust. Rise time, usec

7 Relay output: Relay outputs are with gold plated contacts. Max current Max voltage at contacts: Max voltage according to VDE 0110b (2/79) isolation group A Contact resistance Isolation at 500 V Isolation voltage according to Bellcore TR-NWT (2/10uS) 2A 220V DC /250V AC 150V DC / 125V AC <50mohm / 10mA /20mV 10 9 ohm 2000V Reset signal: Reset signal must be applied for at least 10 sec. AC or DC signal in the range 5-24V. Typical input current 1-4mA At DC input, pin 3 must be negative. External power supply: 230V edition: Connector IEC-320 type B, 3pin, 230V and earth (common connectors). Continuous voltage must be between 196V and 265V V AC editions on request. Power consumption less than 3W. Battery supply: The battery has an expected lifetime of 10 years. The battery lifetime will be shortened dramatically if there is often periods (days) without external power supply. The battery may be changed with a similar 3,7V Lithium battery, when the supervision circuit reports battery failure. The battery supervision circuit will not report failure if the battery is completely disconnected or removed. The battery is not connected at the delivery of the sensor. Temperature range: Antenna: No limits Antenna box and control box: from -20 to +50 degrees Celsius. Materials: Antenna is made of stainless steel. The antenna box and control box is made of EMC tight aluminium. DIN rail adapters on request. Other types of boxes on request. Enclosure: Antennas fulfil IP67. Cables and boxes fulfil IP55.

8 6 5, 0 m m 8, 3 0 c m 5. Mechanical specification Control box: height approx. 75mm above DIN rail 17,90 cm + - Reset 10 sec. Converter box: height approx. 49 mm, but may be changed. 145,0 mm Antenna: Antenna height and width may be changed without notice. 90 degree edition: Cables: The antenna cable is RG58 coax and may be with or without connector at the antenna end. Connector at converter box end is assembled from factory. Optical cable is a 1mm plastic fiber in a 6mm plastic tube and assembled with optical connectors.

9 6. Norms and standards. The lightning sensor system fulfils all relevant EU-Norms and international standards. The lightning sensor is an advanced electronic equipment. Only qualified and electrical educated personal may install the equipment. In case of need for battery exchange etc. the lightning sensor control box must only be opened by qualified electrical educated personal. Due to possible corrosion the boxes may only be opened in short periods of time. 7. Maintenance. a. Initial installation. As soon as the power supply in the turbine is stable, the internal battery may be connected. The battery supervision circuit does not report error when the battery is completely disconnected. The battery is not connected at delivery of the box. b. Maintenance planning It is a good idea once per year to test the lightning sensor. This test may be done by applying a lightning field on each antenna. The battery is designed for a 10 years lifetime at seldom and short drop out of the mains voltage. The battery life time is approx days at missing mains supply. The battery must be changed minimum every 10 years.