Since the total capacity of the accident security load of the desulfurization system is not large, the capacity of the maximum motor is usually more than 20 of the rated capacity of the diesel generator, so it is necessary to install a soft starter on the maximum motor to limit the starting current and avoid excessive selection of the capacity of the diesel generator set.
For wet desulphurization, desulphurization absorption tower is set in the desulphurization island, so lightning protection of the absorber needs to be considered. If the desulfurization island is arranged near the chimney of the main plant, it can first check whether the absorption tower is within the protection range of the chimney. Otherwise, lightning rods are set at the top of the absorption tower to avoid repeated Settings.
For the scheme of setting the desulphurization pressure working transformer, the desulphurization transformer is arranged outside the human column, and the desulphurization pressure distribution device is arranged inside the desulphurization island, so the power supply distance is far, so it is advisable to use the cable power supply. Due to the long cable length, it is recommended to install a protective device between the cable and the desulfurization transformer, that is, a vacuum circuit breaker, in order to avoid the shutdown of the unit when the cable fails.
Due to the rapid development of flue gas desulfurization at present, desulfurization methods are also being improved constantly. For different desulfurization process systems, the electrical system design should not only meet the requirements of existing regulations and standards, but also be designed in combination with the characteristics of the desulfurization system. The above design experience is only a summary of the desulfurization engineering experience in our hospital in recent years, for your reference.
Office, engineer. He once served as the main electrical equipment of hangzhou xiilian coal transformation flue gas desulfurization project, the main electrical equipment of anshun power plant phase I project, the main electrical equipment of anshun power plant phase ii project 2300,07, and baihe power plant phase ii project 23, bei engineering. Address chengdu dongfeng road 18 southwest electric power design institute electric service office postal code 610021 contact number lighting project power supply design questions such as power supply radius, wiring type, protection mode, overvoltage protection, etc. And put forward the solution method through the analysis.
As the national economic development by leaps and bounds, in major cities across the country to spend large sum of money taken to lighting engineering, chongqing at night also because of lighting engineering is known as the city business card, however due to the particularity of its use function, lighting engineering power supply system exist some with conventional building power supply design different q makes, put forward to discuss with our colleagues.
1.1 the power supply lines and distribution equipment of the lighting project are all located outdoors, which are greatly affected by the seasonal temperature difference and the wind and the sun, and are vulnerable to the effect of lightning, so the operating environment is relatively harsh. The design should pay attention to leakage protection; Lightning protection asked; Distribution system earth fault protection, etc.
1.2 in lighting engineering, the illuminator is used in a larger size and has a wider distribution range. Design should pay attention to the selection of appropriate power supply radius; Appropriate leakage protection action current.
1.3 the gas discharge light source is generally used in lighting projects. The starting current is large, the starting time is long, and sometimes there are strong subharmonics. Design should pay attention to the selection of protection characteristics of electrical appliances.
2 ask solution 2.1 power supply radius directly relates to the determination of power supply radius variable distribution substation configuration, power supply radius should meet the requirements of voltage loss, and should satisfy the action time of the single phase short circuit protection and grounding fault sensitivity requirement, with polyethylene, ethylene insulated electric system circuit, for example, assume that lines through the current of rated current-carrying ring 90, the adjusting current protection of long time delay tripping device for line 1 rated carrying capacity of 90, the adjusting current instantaneous trip to 5, For example, 1. Since the section of the line directly supplying power to the lighting equipment should not be too large, only 35 stomach 2 and below are listed in the calculation results. The operation characteristics of 045 short-circuiter are taken as an example. Assuming that the 101-side of the transformer is an infinitely large capacity system, the transformer is taken as an example of 6301.
Meet the voltage loss of single-phase, road ranger acuity grounding, action time requirements of power supply radius around section un2 protection radius meet the voltage loss for single phase short-circuit protection sensitivity for ground fault movement time requirement, you can see that meet the requirements of single phase short circuit protection sensitivity of minimum power supply radius, only hundred meters, namely variable sub-station distance should not be more than 300 meters, the condition is obviously not easy to meet. Therefore, the line section must be enlarged to meet the sensitivity requirements of single-phase short-circuit protection. But in fact, when the line is very long, the single-phase short-circuit current is already very small, which is only equivalent to an overload current for the system, so there is no need to protect the instantaneous action. If only 53 internal action is required, the power supply radius can be greatly increased.
Due to the harsh operating environment, the cable with higher insulation strength should be selected as the distribution line. In addition, the requirement of power supply radius should be considered, and the cross section should be considered between 1035mn12. The distribution radius can reach 250m420m.
2.3.1 in order to ensure the use safety when selecting the 15 wiring system, leakage protection devices shall be set in each circuit. The calculation method of leakage action current is as follows: VV5X25 pipe penetration 70mAkm; W5X16 through pipe laying 62mAkm; VV5X10 pipe laying 56 for 2 fluorescent lamp metal frame installation 0.1ma per set; Leakage data of high intensity discharge lamps are unknown.
Article 535 circuit, for example, if the distribution distance is 400, back to the road by 300 sets of 2361 fluorescent composition in order to ensure the distribution circuit leakage protection misoperation, the leakage protector of leakage protection action current 1 should, therefore, should be much 300 action current of each loop separately leakage protector, not a few common set of leakage protector circuit. [br] as is known to all, when the second grounding fault occurs in the ding system, the fault current is the vector of the other two opposite capacitive currents. The fault current is small and does not pose a hazard to human body. Power supply may not be interrupted to improve the reliability of power supply, and leakage protection is not necessary. However, the system shall be equipped with insulation monitor so as to detect and troubleshoot the faults in time, so as to avoid the occurrence of the second contact fault.
Ting system should not be equipped with neutral line, otherwise when neutral line insulation failure, because the insulation monitor can not detect fault, ding system will become a system operation, no leakage protection is very dangerous.
Therefore, when a special transformer is set for a lighting project, it can be considered to use a 100.23kv transformer and run with neutral point to ground insulation, thus eliminating leakage protection equipment.
2.4 automatic air switch circuit protection feature selection against 2.4.1 due to lighting the gas discharge light source widely used engineering lighting light source, especially high-strength gas discharge lamp, large starting current and time, to avoid misoperation automatic air switch, its protective properties should choose instantaneous action current ratio is big, can avoid starting current of the switch. 2.4.2 lighting engineering lighting has strong simultaneity. In order to avoid overload when the transformer starts up, the distribution loop should be started.
2.4.3 in lighting engineering, due to the light source with heavy harmonics and the use of switching power supply in the control loop, in order to avoid overload of neutral line in system 3, automatic air switch with overload protection of neutral line shall be adopted.
Overvoltage protection lighting project lines and equipment are installed in the outdoor, to prevent the atmospheric overvoltage along the road transmission transformer insulation damage, should be installed in the distribution box lightning arrester for overvoltage protection.
3. Conclusion to sum up, due to the particularity of lighting distribution in lighting engineering, enough attention should be paid to the following aspects when designing the system; 3.1 the power supply line shall be cable line with cross section between 1035mm2.
3.2 the power supply radius shall be limited to 250m420rn according to the size of the cable section used in order to meet the requirements of grounding fault protection and voltage loss.
3.3 in the case of 15 wiring, the action current shall be determined according to the calculation, and each circuit shall be equipped with a separate leakage protector.
3.4 for the special transformer and distribution system for lighting engineering, the distribution type can be considered to use 100.23kv neutral insulated transformer.
3.5 the switch for loop protection shall be an automatic air switch with neutral wire overload protection.
3.6 lightning arrester shall be installed in the distribution cabinet near the transformer for overvoltage protection.
Aviation industry planning, design and research institute of China. Industrial and civil power distribution design manual. Beijing China power 2 quiet. The low voltage distribution distance is determined according to the sensitivity of single - phase short - circuit protection. Guan yuezheng shitong, petroleum exploration and design institute, analyzed the performance selection and requirements of phase asynchronous motors, and emphatically analyzed the similarities and differences of relevant motor protection methods at home and abroad.