Daily safety management of ships-daily maintenance and management of ship electrical equipment
Abstract: The good technical condition of the ship's electrical equipment is the fundamental guarantee for the normal operation of the construction ship of the port and shipping construction unit. Based on my own working experience, this paper briefly describes the principles and methods that should be followed in ship electrical management and equipment maintenance from two aspects: electrical management and equipment troubleshooting, so as to provide relevant reference experience for future management and maintenance.
Keywords: electrical management, maintenance, troubleshooting
China Library Classification Number: C93 Document Identification Number: A
Electrical maintenance and management of ships
Wanjing
(CCCC First Harbor Engineering Co., Ltd. 1 Engineering Co., Ltd. Tanggu, Tianjin 300456)
Abstract: The good technical condition of ship electrical equipment is the fundamental guarantee for the construction of port and shipping construction units and the normal operation of ships. Based on the working experience, this paper expounds the principles and repair methods that should be followed in the usual ship electrical management and equipment maintenance from the management and maintenance of electrical equipment, so as to accumulate relevant experience for future management.
Keywords: electrical management, maintenance, troubleshooting
Our company has 7 1 ship and plays an important role in water conservancy construction. The safe and normal operation of the ship ensures the progress and quality of the construction. The electrical integrity of the ship further ensures the normal and safe operation of the ship. Therefore, it is an urgent and important task to improve the daily maintenance and management level of ship electrical.
The company's ships are both domestic and imported, and the age of the ships is long and short. Its electrical system is complex, including DC and AC, DC has 1 10V and 220V, and AC has three phases: 440V, 380V and 220V. In terms of frequency, there are 50 Hz and 60 Hz. The development of marine electrical technology in recent years makes it more advanced and complex. Many ships adopt computer control technology and frequency converter control technology. This requires us to further improve the technical level and maintenance management level, otherwise it will be difficult to meet the needs of the work.
The marine electrical system is roughly divided into four parts. 1. The ship power station consists of generator set and generator distribution panel, which is the heart of the ship and is responsible for the power supply of the whole ship; 2. Electric drag part; That is, a motor-driven motor, such as a hoist. 3. Lighting and domestic electricity; 4. The emergency system includes communication, navigation, signal lights and navigation lights.
The following is about the daily maintenance and management of ships, and combining with my own work experience, I will talk about my personal views and understanding from the following aspects for your reference.
First of all, be familiar with the electrical wiring and equipment on board.
As a ship manager, we should first be familiar with the ship's electrical wiring and equipment, understand the ship's electrical drawings, understand the differences between symbols and typesetting marks in Chinese and foreign drawings, compare them with drawings in daily work, and understand the positions and types of electrical components displayed in the drawings, so as to understand the drawings and understand them calmly. During the mixed construction of No.5, I checked the drawings with the physical objects, and marked their functions and characteristics on the main relay and contactor. So when something goes wrong, you don't even have to look at the drawings, so it's very convenient and fast to handle. Once, when the computer was measuring cement, the 1# cement auger stopped moving, so it was temporarily used for manual batching and replaced with 1# fly ash batching. When moving the ship on site, it took 10 minutes to visually inspect the relevant wiring of the frequency converter, and decisively replaced the control relay, so that it returned to normal at the end of moving the ship, so that the construction site did not know that the mixing station was in trouble. On another occasion, the problem of motor starting box of crane No.9 was solved. The positions of the components marked on the drawings are ambiguous, such as the marked lifting limit contact, which is thought to be the external contact limit of the cab console, but the external limit is intact. Later, it was found that the microswitch at the lower part of the operating handle also played a role in limiting. This is because I am not familiar with the drawings, and I don't seem to have taken a detour. This situation should be avoided as much as possible in future work.
Second, strictly do it? Daily patrol, monthly inspection, seasonal telemetry and annual maintenance?
1, one-day tour.
Every day at work, we should strengthen the patrol inspection of electrical equipment, focusing on the temperature and abnormal sound of generators and motors, as well as the data of voltmeter and ammeter on the distribution panel. Control all data within the normal range, so as to find out whether there is any abnormality or overload in operation in time, know fairly well and ensure the safety of equipment operation.
2. Check every month.
At the beginning or end of each month, electrical equipment shall be inspected during construction. Focus on checking whether there are loose wiring screws, foreign objects and serious dust in the distribution panel, console and control box, and clean them up in time. Such regular inspection can prevent the occurrence of faults, especially the phenomenon of virtual connection of lines. It is difficult to find faults when they occur, but it is possible to find them in daily inspection, which will nip the faults in the bud and keep the equipment in a good and normal state.
3. Seasonal telemetry.
The environment of ships is worse than that of land, with humid climate, vibration, salt spray and mold corrosion. Therefore, the insulation degree of ship electrical equipment is very important for the safe operation of electrical equipment. The change of season and humidity requires us to know the heat preservation situation at any time. If the motor insulation is found to be declining every time, it means that the winding insulation aging should be removed in time, so it is necessary and feasible to conduct insulation telemetry once a quarter. In addition, the detection of insulation not only has a judgment basis for the preventive maintenance of the motor, but also can disconnect the weak current equipment to test the domestic power system when summer comes, find the lines with low insulation in advance and deal with them, so as to avoid electrical fires caused by water leakage from old ships and prevent electric shock accidents.
4. Annual maintenance.
Every winter, when the project is idle, we should carry out a more thorough preventive maintenance of the electrical equipment on board. Emphasis is placed on motor brakes, bearing grease and slip ring carbon brushes. Another kind of crane, such as No.7 crane, No.9 crane, No.22 crane, No.23 crane and No.26 crane, has a central collector ring, which is also the focus of our maintenance. Because the central slip ring is the main part to send electricity to the crane, it can't be checked at ordinary times. The crane speed is not high, and the carbon brush is not worn much, which is easy to ignore, but it is more troublesome if something goes wrong. For example, during the construction of No.22 lifting in Rizhao, Shandong Province in 2006, the brush holder of the collector ring was loose, which led to the burning of the short-circuit brush holder, and the work was stopped for 3 days after emergency repair, resulting in an indirect loss of 6.5438+0.5 million yuan. Therefore, regular maintenance should be the focus.
Three, the operation points of ship electrical fault repair
1, move first, then do it: For faulty electrical equipment, don't rush to do it, but ask about the process and phenomenon of the fault first. For unfamiliar equipment, we should also be familiar with the circuit principle and structural characteristics and abide by the corresponding rules. Before disassembly, you should be fully familiar with the function, location, connection mode of each electrical component and its relationship with other surrounding equipment. In the absence of assembly drawing, you should draw a sketch and mark it when disassembling.
2. From the outside to the inside: check the equipment for obvious cracks and defects, understand its maintenance history and service life, and then check the inside of the machine. Before disassembly, the peripheral fault factors should be eliminated, and the equipment can be disassembled only after the internal fault is determined, otherwise it may get worse and worse if the equipment is disassembled blindly.
3. Mechanical before electrical: Only after confirming that the mechanical parts are trouble-free, do electrical inspection. When checking the circuit fault, it is necessary to find the fault position with testing instruments. After confirming that there is no poor contact fault, it is necessary to check the operation relationship between the circuit and the machinery in a targeted manner to avoid misjudgment.
4. Static first, then dynamic: under the condition that the equipment is not electrified, judge whether the buttons, contactors, thermal relays and fuses of electrical equipment are good or bad, so as to determine the fault. Power-on test, listen to its voice, measure parameters, judge faults, and finally carry out maintenance. For example, when the motor is short of phase, if it cannot be judged by measuring the three-phase voltage value, it is necessary to listen to its voice, measure the relative ground voltage respectively, and judge which phase is defective. The motor of the square barge 1 18 skip does not operate, and the three phases are not short of power during shutdown monitoring, and the phase of phase B is short during operation: the voltages of 100V and 30V measured when the brake coil of the square barge 86 anchor machine is disconnected are normal, but the voltage measured during operation is insufficient. After line inspection, the voltage drop is caused by the new replacement of the insurance virtual contact.
5. Cleaning before maintenance: For seriously polluted electrical equipment, first clean its buttons, connection points and contacts, and check whether the external control keys are out of order. Many faults are caused by dirt and conductive dust. Such as a computer used in a mixing station.
6. Power supply before equipment: The failure rate of power supply part accounts for a high proportion in the whole faulty equipment, so repairing power supply first can often get twice the result with half the effort. For example, the control of the barge 1 18 windlass is out of order.
7. General first, then special: faults caused by the quality of assembly parts or other equipment faults generally account for about 50% of common faults. The special faults of electrical equipment are mostly soft faults, which need to be measured and maintained through experience and instruments. For example, mixer No.5 and mixer No.2 stop during heavy load operation, which seems to indicate that the load capacity of the inverter is insufficient. However, careful analysis shows that the virtual connection of inverter operation control circuit is serious under the condition of heavy load vibration, which leads to the open circuit of inverter operation signal and the shutdown of inverter system. ?
8. Peripheral first, then internal: Don't replace the damaged electrical components in a hurry, and then consider replacing the damaged electrical components after confirming that the peripheral circuit is normal. If the navigation light of handover 25 fails, the obvious phenomenon is fusing. It is necessary to consider why the fuse is accidental or the inevitable result of the line problem, and find that the short circuit is caused by the damage of the insulation layer of the external line. ?
9. DC before AC: During maintenance, the static working point of DC circuit must be checked first, and then the dynamic working point of AC circuit must be checked. In the multilevel control system, because the voltage of the 24V control line is relatively low, the response to the virtual connection of the line is more obvious than that of the AC circuit, and the voltage drop of several volts is enough to cause the abnormal action of the relay. If the windlass control of the barge 1 18 occurs, all windlasses will not work. After investigation, it was found that the AC 24V rectifier failed and the emergency 24V intermediate relay switched automatically. The contact resistance is greater than 30 ohms, which causes the voltage to drop obviously during operation and cannot work.
10. Fault before debugging: For electrical equipment with both debugging and fault, the fault should be eliminated before debugging, and debugging must be carried out on the premise that the electrical circuit is normal.
Fourth, master the correct detection methods.
1, intuitive method. Intuitive method is a method to check and judge electrical faults by looking, smelling and listening according to their external manifestations. Inspection steps: ① Investigation: Ask the operator and the personnel at the fault site, including the external performance, approximate location and environmental conditions when the fault occurs. Such as whether there is abnormal gas, open flame, whether the heat source is close to electrical appliances, whether there is corrosive gas intrusion, whether there is water leakage, whether someone has repaired it, the content of maintenance and so on. (2) Preliminary inspection: according to the investigation, check whether there is any damage on the outside of the electrical appliance, whether the connection is broken or loose, whether the insulation is burnt, whether the fuse indicator of the spiral fuse jumps out, whether the electrical appliance is flooded or greasy, and whether the switch position is correct. (3) Debugging: After the initial inspection confirms that the failure and personal and equipment accidents have not been further expanded, further debugging inspection can be carried out. During debugging, attention should be paid to whether there is serious fire, abnormal smell and abnormal sound. Once found, the power should be cut off immediately. Pay attention to check whether the temperature rise of electrical appliances and the action program of electrical appliances meet the requirements of the schematic diagram of electrical equipment, so as to find the fault parts.
2, comparison, replacement parts, gradually open (or access) method. ① comparison method: compare the test data with the drawings and normal parameters recorded at ordinary times to judge the faults, such as panel indicator light, LED of intermediate relay, input point of PLC, etc. For electrical appliances with no data and no usual records, they can be compared with those with the same model in good condition. When the electrical components in the circuit belong to the same control property or multiple components control the same equipment, the fault can be judged by the actions of other similar or identical power supply components. ② Component replacement method: When the fault causes of some circuits are difficult to determine or the inspection time is too long, but in order to ensure the utilization rate of electrical equipment, we can replace components with good in-phase performance to confirm whether the fault is caused by the electrical equipment. ③ Step-by-step open circuit method: When the electrical insulation on the ship is poor, the step-by-step open circuit method is often used. That is, when the insulation of the ship is very low, the equipment disconnects 1 loop and in the distribution box 1 loop. When the insulation meter of the switchboard indicates that it is suddenly normal, the last separated circuit is the fault circuit.
3. Resistance measurement method can be divided into step measurement method and subsection measurement method. These two methods have their own advantages. Step-by-step measurement method is generally simple for lines, which is convenient for measuring the situation of each measuring point at the same place; Sectional measurement is generally used when the control loop is complex and long, and the control system is not in the same box. Sectional measurement is usually used in combination with hierarchical measurement. Resistance measurement method is sometimes influenced by parallel circuits in circuit analysis, which will mislead our judgment, and sometimes it is necessary to remove the lines for measurement. The following is a description of the electrical schematic diagram of the air compressor.
For example, when there is an electrical fault, the power indicator light is on, and it works normally when it is automatic. When the start button is manually pressed, the operation indicator light does not light up and the contactor does not engage. Because the automatic operation is normal, it can be judged that the contactor and indicator light are not damaged, and we can judge the line by resistance method. For this simple circuit, we directly adopt the method of step-by-step measurement. The start-up of the air compressor requires the contactor to pull in, and both ends of the contactor coil need to be connected to the secondary end of the transformer respectively. We need to find out which end of the contactor coil is not connected to the transformer. Before measuring, we need to find a reliable pilot as a starting point. Because the automatic operation is normal and lines 02 and 04 are normal line points, we can measure 02- 13, 04- 10, 04- 1 1 2 by pressing the start key. 04- 1 1 is closed, so the fault point is between10-1. Measure that the remote stop button is closed, and replace the stop button for troubleshooting. It should be noted that the resistance between buttons is not directly measured separately to prevent the line terminal board or cable from breaking.
4, measuring voltage method. The method of voltage measurement is to measure the voltage or current value of each point according to the power supply mode of electrical appliances and compare it with the normal value. Specifically, it can be divided into step-by-step measurement, subsection measurement and point measurement. The basic analysis is similar to the resistance method. The main contactor of air compressor needs to have rated working voltage at both ends of the main contactor coil. The transformers in the picture are 380V to 220V transformers. During the test, we pressed the start key, and the voltages between 13-03 and 12-02 were AC220V and 86V, respectively, indicating that the power supply of 12 line was not delivered, the stylus of line 02 was not moved, and the other stylus measured1/kloc-in turn. If the voltage changes between 1 1 and 10, the fault point is between 10 and1,that is, the contact of SB3 stop button is damaged.
5. Short connection method. The faults of equipment circuits or electrical appliances can be roughly divided into six categories: short circuit, overload, open circuit, grounding, wiring error, electromagnetic and mechanical part faults of electrical appliances. Among all kinds of faults, open circuit fault is the most common one. Including disconnection, virtual connection, looseness, poor contact, virtual welding, false welding, fuse blowing and so on. In addition to resistance method and voltage method, there is a simpler and more reliable method, that is, short circuit method. The method is to short-circuit the suspicious open circuit with a well-insulated wire. If there is a short circuit somewhere, the circuit will return to normal, indicating that it is an open circuit.
The above inspection methods should be learned and applied flexibly, and the safety operation procedures should be observed. For parts that burn out continuously, find out the reason and then replace them; When measuring voltage, the voltage drop of conductor should be considered; Do not violate the principle of equipment and electrical control, never leave the power switch when debugging, and use the same amount or slightly less than the rated current for insurance; Pay attention to the selection of measuring instrument gear.
Overhaul requires extra care. Even so, unexpected mistakes still happen from time to time. Pay special attention to the following situations: the wires removed during maintenance must be wrapped with insulating cloth; Replace fuses and switches according to the original model or capacity; When replacing the equipment with rated working voltage, check whether the working voltage of the equipment is consistent with the maintenance equipment; Whether maintenance tools are left in the control cabinet after maintenance. In fact, the above mistakes are often caused by the carelessness of maintenance personnel. In order to prevent these accidents, considering the requirements of the electrician's safety operation specification, the maintenance work should be completed by at least two people, one for operation and one for monitoring, and the key operations should be confirmed at the same time.
Five, prepare the necessary spare parts
Unlike land, ships are often built at sea or other places, and sometimes parts are damaged beyond repair. If it is not replaced, the normal production and construction of the ship will be affected, and even safety accidents will occur in bad weather, so it is very important to have enough spare parts. Moreover, the variety of spare parts should be complete, but the quantity should not be too much, so as not to cause unnecessary investment and backlog. The key is to replenish it in time when it is used up.
Sixth, attach importance to ship inspection.
We know that CCS should inspect the ship as planned. Conduct an annual inspection every year. Conduct dock inspection twice every five years and conduct regular inspection once every five years. Regular inspection requires marine electrical to do the following work: 1, generator load test: this is mainly to examine the performance of the prime mover. Do load test with dry resistance or water resistance, and carry out sudden loading and unloading load test from no-load to full load; 2. Verify the air switch of the generator switchboard; And counter-current (DC) and reverse power (AC) tests during parallel operation. This is mainly to ensure the safe power supply of the generator. There are over-current, under-voltage, step-by-step unloading and other projects. Over-current has short delay, long delay and instantaneous trip test; 3. Verification of electrical instruments: ammeter, voltmeter, frequency meter, power meter and other instruments on the distribution panel. The inspection shall be carried out by a qualified inspection unit and a certificate shall be issued; 4. Wind-oil parking test: Set a button at the engine room entrance. In case of emergency fire, press this button to stop the axial flow fan, fuel pump and air conditioning fan in the engine room; 5. Navigation light and signal light system test: mainly to see that when the filament of the light bulb is broken (the light goes out), it should give an audible (optical) alarm. At ordinary times, we should strengthen the maintenance of these related equipment, find faults in time, eliminate hidden dangers and make them in normal working condition.
Seven, strengthen electricity safety and fire prevention management.
The safety of ship power consumption is more important than land. The electrical system of this ship is different from that on land. General ships use three-phase grounding? In the system, the lighting voltage is obtained by an isolation transformer. There should be no potential to the ground (that is, the shell), so when the grounding light is on or the insulation monitor gives an alarm, attention should be paid to eliminating the grounding fault. In addition, due to the improvement of living standards, more and more electric cookers are used on board. Rice cookers, electric steamers, electric frying pans and electric tea stoves are frequently used, with high power, above 1.5KW and current above 15A. Pay close attention to their sockets. A few years ago, the 15A porcelain socket was inspected and replaced. In the future, we should continue to pay attention to the sockets, plugs and wiring of rice cookers and check them regularly. Prevent the plug from loosening and heating to cause failure. In addition, the existing air conditioners are mostly used for home or office use, which can not meet the marine protection standards and flame retardant standards. Therefore, the management of air conditioning should be strengthened. Advocate the use of single-cooling air conditioners and add electric heaters for heating. The air conditioner has high heating power, low efficiency and short service life (it is difficult for the indoor temperature to reach the set temperature in the case of poor insulation environment and will not stop running for a long time). In addition, the electric heater is used on the ship, and there is also a domestic oil-filled one with angle wheels, which is extremely unsafe. Therefore, it is necessary to strengthen the inspection to avoid problems.
In addition, some of our ships' wires are aging for a long time, so it is not easy to find problems by checking hidden wires. We should pay more attention to them at ordinary times and handle them in time if any abnormality is found. When connecting shore power, everyone should pay attention to the terminals in the shore power box and tighten the insulating bolts. At present, the bolts in the dock box are seriously lost, so don't remove them, and stop others from removing them, otherwise it will be inconvenient. The company has invested so much money for safety, and this TEU is for safety and should be taken care of.
Concluding remarks
The contents summarized above, as my own personal experience and some experiences, are more in line with the reality of ship management, have better operability, are more suitable for the crew to carry out daily maintenance and operation, and have a standardized role for managers. As a ship electrical technology manager, we should not only pay attention to our own theoretical study, but also be good at summing up in practical work, write down the faults and hidden dangers encountered in our work, analyze the reasons, find solutions, and pass on our experience to the crew and colleagues, so as to refine the ship management work, not to be an armchair strategist, and strive to improve our on-site solving ability and become a qualified ship manager.
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