Wednesday, December 29, 2010

【 Weak current College 】 high-voltage circuit breakers refused to jump and refused-causes and solutions 】

Substations to load stop, power transmission, critical equipment is a high-voltage circuit breakers, also called high pressure oil switch, it is good or bad decision directly to the entire distribution system correctly, is the high-voltage supply and distribution system most prone to failure of vulnerabilities affecting high voltage circuit breaker does not work a number of factors, mainly present in human factors and the device itself factors and many other reasons, which are summarized as follows:

1, high-voltage circuit breaker does not switch on power transmission, this phenomenon is known as the high voltage circuit breaker switch to refuse this behavior with the phenomenon, in the scene of the accident occurs frequently.
2, high-voltage circuit breaker does not break brake power outage, this phenomenon is known as high-voltage circuit breakers refused to jump in the scene accident treatment, this phenomenon is widespread.
3, also affect the oil switch does normal and closing phenomena, is due to a switch, fuse, tripping fuse protection link breakage, damage control switch failure for many reasons, those reasons at the scene of accident treatment is very easy to determine and resolve, here not in detail.
How to keep it reliable and secure operation, is the substation equipment management priorities. Following the high-voltage substation circuit breaker rejection, refusal to skip the symptom, combined with practical, explain it solutions.
First, high-voltage circuit breakers refusal causes kg
1, high-voltage circuit breakers refused to close, high-voltage switch cabinet, after the overhaul of the debugging operation substation watch, high voltage circuit breaker for the first time, closing and opening operations are normal, but when the second closing time, resulting in rejection of hop phenomenon. Accident alerts are normal movement, sound and cue signals.
2, high-voltage circuit breakers refused-cause analysis, on-site check protection circuit connection are consistent with the original drawings, repair process does not appear the replacement unit and transform the wiring, which is why? check found that as long as a high-voltage circuit breakers break brake, skip it sucks merge relay TBJ stay. TBJ is in high voltage breaker by its current coil when started. Once started, TBJ normally open contact closure, signal voltage coil LD and TBJ-line ends, 220V control power plus in LD and TBJ voltage coils at both ends. LD for energy-saving lights, its equivalent resistance around 22 k Ω T B J as intermediate relay DZB-15B/220V, 0.5A type, its voltage DC coil resistance 9 k Ω. After finding information and calculated, LD voltage-156V, TBJ voltage to 64V, field test and calculate basic match, this intermediate relays of voltage standards by factory returned to not less than the rated voltage of 3%, thus causing a second closing of the phenomenon is due to the rejection-TBJ voltage coils are sufficient to maintain voltage, so cut off switch on the circuit.
3, solutions
(1) in the LD light circuit breakers series a close regular contact, when high-voltage circuit breaker, TBJ voltage winding is not flowing currents, of course, will not have to maintain voltage. When high-voltage breaker, both to monitor high voltage circuit breaker is good, but also can indicate whether they are opening.
(2) the LD wiring from line 3 to 5 lines after the TBJ action with its LD voltage winding down, but this approach in certain high-voltage circuit breakers actuator to alter its wiring within more hassle.
(3) if the high-voltage circuit breakers have no spare normally closed auxiliary contacts, TBJ voltage coil ends parallel a additional resistance R, TBJ voltage coil voltage not greater than the rated voltage of less than 30%. Calculate select resistance ZG11 — 50/600 Ω, and checking. Parallel 600 Ω resistor, LD voltage to 214V, TBJ voltage coil voltage to 5.5V.
4, two description
(1) high voltage circuit breaker tripped State, to calculate the additional resistance power 0.05W. Taking into account the direct voltage 220V during closing plus additional resistance, although switching power on time is very short, but the power can not be selected is too small, this case select 50W, can satisfy the requirements for safe operation.
(2) in the event of accidents, to calm, constant sum up the previous accident, summary, identify the most simple processing methods and procedures, the accumulation of experience, as the next of accident processing provides experiences and lessons learned.
2. high-voltage circuit breakers refused to jump analysis
1, high-voltage circuit breakers refused to jump in, on-duty officers found with a high-voltage switch cabinet exception display overload run 20 seconds, the transformer secondary switch tripping, but the distribution out of the Cabinet did not trip, with a high-voltage switch cabinet after the power failure does not display the exception. Watchkeeping personnel grounding selector will be elected outage. Other high-voltage switch cabinet, power supply correctly.
2, high-voltage circuit breakers rejection reasons, to jump on duty personnel about the accident and the detailed examination, considered to be the holder of the cause of the substation of the trip. Check the cabinets found overcurrent relays of the normally open contact GJ burned, after we all consider that this failure is caused because it up, but I and drawings and information check found is not a direct result of this cause of high-voltage circuit breakers refused, if the overcurrent relays of GJ contacts due to load big moments burning, then in burned while tripping circuit also through, constitutes the tripping of the conditions, should not be refused to jump? after the attendant the Cabinet side know this accident had prior to the trip record, because there was no pressure on the trip detail check on Cabinet tripping of a high-voltage Cabinet, strong andtransmission power. At that time did not find the Cabinet have any unusual phenomena, there is a result of overcurrent relays dark shell, with the result that the person on duty did not see and check to this point GJ contacts have already burned in and in front of transmission examination nor good inspection equipment, GJ contacts and HD loop in parallel, so when the power switch on the power indication light is on, the appearance of a wrong signal that trip circuit no short-term and failed, the next accident trip time overcurrent relays body movements, but at this point GJ contacts have already broken theOpen, you cannot leave the high voltage circuit breaker tripped and normal, causing the high-voltage circuit breakers refused to jump, a trip by accident.
3. settlement method
(1) strengthening substation watch officer of the business knowledge of learning and training, the organization staff in case studies and analysis to identify issues and gaps, and constantly corrections, gradually let watchkeeping personnel are familiar with the application of knowledge and on the exceptions and accident analysis, judgement and timely processing of capacity strengthening against accidents, accidents, such as learning and expected experience, constantly absorbing and deal with incidents of summary, mutual experience and lessons learned from the same people for accidents.
(2) on high-voltage switch cabinet to strict management, accident trip of switch cabinet not to have to figure out what the cause, the command transmission, so the personnel and equipment are not good, but also to expand the scope of the accident, the reasons for the non-normal trip of high-voltage switch cabinet outage, timely inspection and testing and debugging, to let the power distribution unit foolproof circumstances can be put into operation.
(3) to standardize the Substation site operation regulations, to the point of guide system refinement, watch each step should do, do not let the personon duty have ambiguous situation. On every step, every subtle link to do work of uniqueness, this will not only be able to guarantee the safety of personnel, and to protect the integrity of the device.
Closing remarks
This high-voltage switch cabinet retrofit does not appear after the same accidents. High voltage power supply is not conclusive evidence to that effect, from design to run to the operation in accordance with the procedures and systems to deal with the constant practice and system specification, only on the device the application of the familiar and in order to better protect the safety of persons and equipment, to a more rational and effective use of equipment in order to guarantee the normal power supply transformer substation safety.

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