(1) the possibility of introducing a large number of
On the power grid in the system power, the large scale of power generation efficiency, economy Gao, due to these advantages, atomic energy, fire, water, etc. account for most of the power supply. However, as represented by the carbon dioxide lead to global warming emissions of gas and hazardous substances system constraint conditions, the future very difficult for new or additional thermal power. In addition, nuclear power generation options because of location problems, its long construction period, and hydroelectric power, as has been the main location, almost all basic can not be expected to generate new supply. In this case, the fuel cell as a high-efficiency, environmental load small decentralized power by the people's attention.
In terms of power generation systems, fuel cells can be small ①; location constraints; ③ The construction period is short, so people look forward to its electricity network in the future large-scale power in the supplement and perfect to play an important role.
From the perspective of social system, with the relaxation of regulations and the development of electricity market liberalization, the increasing popularity and expanding the fuel cell, and has been improved, Lenovo K42 battery that in October 1995 under the revised method of electrical utilities, has allowed new businesses join the power generation sector, small-scale power system connection, the wholesale shipment from the shipment so. In March 2000 began a part of the liberalization of electricity retailing. Expected in the future, new join will expand the number of power grid, fuel cells can also be introduced this way. From the above environment, systems, society and future fuel cell cost reduction and other comprehensive factors into account, it can be said with the introduction of the grid based on a large number of fuel cells.
(2) a large number of systems connected a technical issue
A large number of fuel cells connected by the system, the previously discussed issues will be further expanded, the following are particularly important issue.
① voltage generation and increasing the current radial distribution system, and can not be assumed that there is power distribution system side. Side of the voltage distribution system management, is really just under one-way from the substation to the user to design and use flow. In such a distribution system, if the introduction of a large number of fuel cell, reflux can occur, resulting in system voltage by the electric side up. So that the existing distribution line voltage controlled conditions will produce the following questions. (A) Although you can use wire taps to manage column transformer low voltage distribution line voltage, it is difficult to properly manage the resulting rise in counter-current voltage; (b) the output power distribution substation line voltage electricity is usually stored as by units to control, when the power distribution lines between units of the load characteristics to a significant differences, we can not properly control voltage; (c) wind power and solar power generation a large number of systems connected, Toshiba Satellite M45 battery possible voltage of 101 ± 6V range Mainland frequent changes . However, changes in fuel cell power generation small, very few such problems.
② Short-circuit capacity increases with the fuel cell system connected to the power network when a short circuit accident, fuel cells will become the emergency current supply source, therefore, short-circuit capacity than the introduction of fuel cells are not bigger context. In the case of short circuit capacity increases, once the circuit breaker over-capacity has been established, when the accident can not be open circuit. However, the inverter can inhibit short-circuit current, over-current protection device for more than 2 times the rated current of the instantaneous overcurrent will play a role, this time the increase will not cause a short circuit capacity.
③ separate operation because a large number of low detection sensitivity of the introduction of fuel cell, power generation equipment and load active power and reactive power when in balance, there will be for passive mode voltage relays and frequency relays can not detect the insensitive zone. In addition, there is increased sensitivity to increase the probability of malfunction and reduce the sensitivity of the subject is not sensitive to area expansion. On the other hand, the active form, HP Mini 5101 battery because a lot of settings with a variety of separate detection of the fuel cell operation, prone to interference, so the detection sensitivity decreased, and the active form will create overlap interference signals cause the system power quality deterioration.
In summary, whether active or passive mode means a lot in introducing fuel cells, the individual will become a problem running test. Therefore, the need to develop a reliable power grid does not affect the detection method.
④ high harmonics increases the fuel cell DC power generation system connected to the electricity network, the need to use the DC-AC inverter converts. From the principle, said the device is the source of high harmonics occur, so to comply with the guiding principles of higher harmonics for system connection. When the large scale introduction of fuel cells, although each cell can meet the requirements of the target level, but the total voltage distortion rate is often more than the target level. Power grid high harmonic generated hazards, so the number of successive increase in Taiwan, it must correctly grasp the situation.
⑤ The following other topics are all concerned about power quality issues. (A) to increase the output DC component of DC power equipment to the power grid out of the DC component in the control of 1% in nominal, but with the system to increase the number of connected units, these outflows will overlap, to adversely affect electrical equipment; ( b) production of high-frequency clutter inverter carrier frequency as the relationship between the generated high frequency clutter (clutter conduction, radiation clutter>.When the capacity and equipment to increase the number of cases and lead to equipment damage and other issues . In addition, the following items as a grid, use and design programs in such areas as issues. (a) fuel cells together to stop the overload generated when the instantaneous voltage is low and the distribution line accident, will stop the fuel cell together, the result will occur including the time again, including closed circuit overload; (b) the system's problems switching between the two systems, when one side of a large number of distributed power is the system connected, the system at the end of the system voltage and the difference angle will change large, the system will be difficult to switch. In addition, when switching to stop the fuel cell, HP ProBook 4310s battery it must also consider the use of the issue; (c) the actual state of load management, the whole process of monitoring and other issues from the grid, fuel cells can not be monitored the case of output power, we can not grasp the total needs of the management of the load so it will become difficult; (d) equipment, using the issue plan load electricity needs and difficult to predict the rate, then increase the period of the equipment becomes difficult to judge properly. the results will lead to excess investment in equipment and supply reliability of the decline. Also, according to the specific circumstances of power grid in the implementation of system changes and the time line construction, etc., necessary to confirm again that links the fuel cell system capacity and voltage protection systems such as link conditions change.