Monday, February 21, 2005
The Array - Chapter 2 - Short Circuit
Dish 5 - Phase Loss 21:20:18
Dish 6 - Phase Loss 21:20:18
Dish 49 - Carrier Sync Loss 21:20:18
Data Buss A - Undervoltage 21:20:18
…
Jensen's already loose handwriting style was becoming more chaotic by the second as fatigue set into his wrist and lower arm. Four pages of alarm logs from a single incident and still two more control sections to clear.
More worrying though was that the main trunk 'ready' light had not lit up again, indicating that this was a little more than a glitch in the system. After transcribing each page of alarms the system takes a second or two to acknowledge them across the various processors on the distributed control system. The price paid for redundancy is a hit in performance, though it gives Jensen a moment to check the status of the main data buss in between pages.
Charles in the meantime was cursing his procrastination in calling the draftsmen back to re-organize the drawings into their proper order in the plan cabinets. Usually the drawings are kept in impeccable order with all of the electrical drawings grouped and ordered by number, as are the civils drawings, the general arrangement drawings and all of the vendor drawings.
A month back, Consolidated Drafting had been commissioned to convert the paper drawings to an electronic format. The cabinets had been removed for a week and returned like a deck of shuffled cards. This in itself wouldn't have been so much of a problem if the electronic format of the drawings had been delivered on schedule, but with experienced draftsmen being in high demand in the mining and construction industries at the moment left Consolidated Drafting more than a little shortstaffed.
This left Charles with the perplexing problem of locating the main buss civil and flow drawings in the mess that was left. It had entered Charles' mind that it would be easier finding a name in a yellow pages directory if it had been sorted by street number rather than surname.
Finally the last screen of alarms had been acknowledged and Jensen could move on from the archaic, and overly beauracratic nonsense of recording digital data in longhand when a $50 dot-matrix printer would do the job in under a minute.
His next task was to try to make some sense as to what happened. Why did we lose the entire feed? The simplest solution would be if the breaker tripped, but he didn't recall any overcurrent alarms in the logs. It was possible that heat could cause a trip though, and if a fan in the main power buss cabinets had stopped, then that could be a cause.
Unlikely as this scenario was, Jensen needed to be certain that a simple circuit breaker wasn't the cause of the shutdown tonight.
"I'm just going to check the buss breakers in the Control Centre. Can you keep an eye on the panel"
"If something goes down again, we'll be able to hear the screaming from central." Came the short reply from Charles. "Just find out where the problem is and hurry back. I've got a little bit of a paperwork crisis here."
Jensen, not wanting to push his luck any further than necessary was out exit like a shot, and across the yard to the featureless white building that appeared to be supported by the massive braids of wires that passed through the floor.
Jensen took the three steps to the door in a single bound and in the same motion had his security key into the lock. The blast of cold air from the air conditioners mussed his wavy brown hair as he pulled the door open.
Jensen strode down the passageway between the wall and the first row of electrical cabinets, reading the engraved identification tags as he went.
110 V Utility Buss
110 V Lighting Buss
110 V Filtered Buss C
110 V Filtered Buss B
110 V Filtered Buss A
Data Trunk D
Data Trunk C
Data Trunk B
Data Trunk A
That was the one he was after. Hurriedly, Jensen inserted Charles' cabinet key into the lock on the front panel. The door opened, indicating that the breaker had tripped. The locking mechanism would not have allowed the panel door to open if the breaker was armed. The smell of ozone and melted plastic greated Jensen as the grey panel door swung open.
He glanced up at the door and noted that the fan was still spinning. That ruled out the over-heating, though melted plastic normally indicated something a little more severe. Both the hot and the cold buss bars on both sides of the contactor showed scorch marks on the contactor housing, indicating a short circuit between these busses, somewhere after the contactor, or simply a catastrophic contactor breakdown. The main breaker for the buss had also tripped, which wasn't surprising.
The hot and the cold busses always carried an identical signal but flipped in amplitude. This allowed for better noise rejection along the 28km line to the splitting station. With signals as large as the ones being sent from the Information Defence Syndicate, if the two busses ever touched each other, then some serious current could flow.
Hopefully the shortcircuit hadn't made it back as far as the main amplifier, or damaged the phase lock circuits or signal mixer which used the amplified signals as their control signal.
It's these two circuits that usually allowed the signal to be transferred smoothly from one buss to another without any glitches in the system, but there needs to be a signal on both busses for the system to work. Why they don't just use this system to transfer the signal in case of phase loss or signal loss left Jensen bewildered, but then again, it was a government department. In anycase, the contactor looked toasted despite the fast lockdown by the circuit breaker, and would have to be replaced before the data trunk could be tested again.
Jensen picked up the receiver of the brown telephone hanging on the wall, and keyed in the number of electrical supervisor. While Jensen was qualified to replace electrical components, he'd rather leave the big equipment to that slightly crazy breed of electricians who lived on the adrenalin associated with working with big currents and high voltages.
The phone only rang twice when a young voice answered on the other end.
"Hello"
"Oh Hi Benjamin, it's Mr Jensen here from your dad's work. Could I please speak with your dad?"
"Dad - phone" emerged the distorted shout from the receiver at Jensen's ear just before a loud crack as Jack dropped the receiver onto the table at the other end.
In the 20 seconds or so that it took for Jack Fleming to pick up the receiver, the ringing in Jensen's left ear had reduced to an annoying tinnitus level.
"Yo" came the Australian accent from the other end.
"Hi Jack, it's Jensen here at the array feed. We've just lost the main data trunk, and the contactor looks fried. Any chance you getting one of your boys down here to replace it, so that we can test the trunk?"
"Struth. What didya do, get hit by lightnun or sumthun?"
"We're not sure yet, but Charles is running scared after a call from the president's office."
"Sounds serious. I'll pop over straight away. In the mean time, can you check the status of the amp for me. If the contactor's gone, then the surge may have made it back to the amp. Any light except red is good. If there's no light, then that's bad."
"I'm heading over there now. If there's a problem with the amp, I'll be waiting for you in the Control Centre, otherwise I'll be back in the control room helping Charles find the schematics for the data buss.
"No worries mate. Cya soon."
Dish 6 - Phase Loss 21:20:18
Dish 49 - Carrier Sync Loss 21:20:18
Data Buss A - Undervoltage 21:20:18
…
Jensen's already loose handwriting style was becoming more chaotic by the second as fatigue set into his wrist and lower arm. Four pages of alarm logs from a single incident and still two more control sections to clear.
More worrying though was that the main trunk 'ready' light had not lit up again, indicating that this was a little more than a glitch in the system. After transcribing each page of alarms the system takes a second or two to acknowledge them across the various processors on the distributed control system. The price paid for redundancy is a hit in performance, though it gives Jensen a moment to check the status of the main data buss in between pages.
Charles in the meantime was cursing his procrastination in calling the draftsmen back to re-organize the drawings into their proper order in the plan cabinets. Usually the drawings are kept in impeccable order with all of the electrical drawings grouped and ordered by number, as are the civils drawings, the general arrangement drawings and all of the vendor drawings.
A month back, Consolidated Drafting had been commissioned to convert the paper drawings to an electronic format. The cabinets had been removed for a week and returned like a deck of shuffled cards. This in itself wouldn't have been so much of a problem if the electronic format of the drawings had been delivered on schedule, but with experienced draftsmen being in high demand in the mining and construction industries at the moment left Consolidated Drafting more than a little shortstaffed.
This left Charles with the perplexing problem of locating the main buss civil and flow drawings in the mess that was left. It had entered Charles' mind that it would be easier finding a name in a yellow pages directory if it had been sorted by street number rather than surname.
Finally the last screen of alarms had been acknowledged and Jensen could move on from the archaic, and overly beauracratic nonsense of recording digital data in longhand when a $50 dot-matrix printer would do the job in under a minute.
His next task was to try to make some sense as to what happened. Why did we lose the entire feed? The simplest solution would be if the breaker tripped, but he didn't recall any overcurrent alarms in the logs. It was possible that heat could cause a trip though, and if a fan in the main power buss cabinets had stopped, then that could be a cause.
Unlikely as this scenario was, Jensen needed to be certain that a simple circuit breaker wasn't the cause of the shutdown tonight.
"I'm just going to check the buss breakers in the Control Centre. Can you keep an eye on the panel"
"If something goes down again, we'll be able to hear the screaming from central." Came the short reply from Charles. "Just find out where the problem is and hurry back. I've got a little bit of a paperwork crisis here."
Jensen, not wanting to push his luck any further than necessary was out exit like a shot, and across the yard to the featureless white building that appeared to be supported by the massive braids of wires that passed through the floor.
Jensen took the three steps to the door in a single bound and in the same motion had his security key into the lock. The blast of cold air from the air conditioners mussed his wavy brown hair as he pulled the door open.
Jensen strode down the passageway between the wall and the first row of electrical cabinets, reading the engraved identification tags as he went.
110 V Utility Buss
110 V Lighting Buss
110 V Filtered Buss C
110 V Filtered Buss B
110 V Filtered Buss A
Data Trunk D
Data Trunk C
Data Trunk B
Data Trunk A
That was the one he was after. Hurriedly, Jensen inserted Charles' cabinet key into the lock on the front panel. The door opened, indicating that the breaker had tripped. The locking mechanism would not have allowed the panel door to open if the breaker was armed. The smell of ozone and melted plastic greated Jensen as the grey panel door swung open.
He glanced up at the door and noted that the fan was still spinning. That ruled out the over-heating, though melted plastic normally indicated something a little more severe. Both the hot and the cold buss bars on both sides of the contactor showed scorch marks on the contactor housing, indicating a short circuit between these busses, somewhere after the contactor, or simply a catastrophic contactor breakdown. The main breaker for the buss had also tripped, which wasn't surprising.
The hot and the cold busses always carried an identical signal but flipped in amplitude. This allowed for better noise rejection along the 28km line to the splitting station. With signals as large as the ones being sent from the Information Defence Syndicate, if the two busses ever touched each other, then some serious current could flow.
Hopefully the shortcircuit hadn't made it back as far as the main amplifier, or damaged the phase lock circuits or signal mixer which used the amplified signals as their control signal.
It's these two circuits that usually allowed the signal to be transferred smoothly from one buss to another without any glitches in the system, but there needs to be a signal on both busses for the system to work. Why they don't just use this system to transfer the signal in case of phase loss or signal loss left Jensen bewildered, but then again, it was a government department. In anycase, the contactor looked toasted despite the fast lockdown by the circuit breaker, and would have to be replaced before the data trunk could be tested again.
Jensen picked up the receiver of the brown telephone hanging on the wall, and keyed in the number of electrical supervisor. While Jensen was qualified to replace electrical components, he'd rather leave the big equipment to that slightly crazy breed of electricians who lived on the adrenalin associated with working with big currents and high voltages.
The phone only rang twice when a young voice answered on the other end.
"Hello"
"Oh Hi Benjamin, it's Mr Jensen here from your dad's work. Could I please speak with your dad?"
"Dad - phone" emerged the distorted shout from the receiver at Jensen's ear just before a loud crack as Jack dropped the receiver onto the table at the other end.
In the 20 seconds or so that it took for Jack Fleming to pick up the receiver, the ringing in Jensen's left ear had reduced to an annoying tinnitus level.
"Yo" came the Australian accent from the other end.
"Hi Jack, it's Jensen here at the array feed. We've just lost the main data trunk, and the contactor looks fried. Any chance you getting one of your boys down here to replace it, so that we can test the trunk?"
"Struth. What didya do, get hit by lightnun or sumthun?"
"We're not sure yet, but Charles is running scared after a call from the president's office."
"Sounds serious. I'll pop over straight away. In the mean time, can you check the status of the amp for me. If the contactor's gone, then the surge may have made it back to the amp. Any light except red is good. If there's no light, then that's bad."
"I'm heading over there now. If there's a problem with the amp, I'll be waiting for you in the Control Centre, otherwise I'll be back in the control room helping Charles find the schematics for the data buss.
"No worries mate. Cya soon."
# posted by The Puppeteer : 5:43 pm
