Research On The Characteristics Prevention And Control Of The Runaway Operating Mode In The Power System

There have many examples caused by the unexpected reasons that can make the system into the runaway operating mode in the operation of the power system in many industries. The runaway operating modes occur usually accompanied with the transient phenomena. The transients will do harm to the system in some degree. The lighter will make the equipments break down which make the system can not work normally; the heavier will cause the grievous consequences such as the stopping of the production or the injuries and deaths. So the runaway operating mode particularly the prevention and control of the transient intensity must been paid the most attentions. And it is important to find out the methods that can control the transient intensity when the runaway operating modes occur and can be used to conduct the production in order that there have not the transient phenomena when the system is working or it will cause the least harms that can avoid the economic loss even if the phenomena occurred.On these grounds, I have made the experimental researchand theorical analyse about the typical runaway operating mode. The main contents and conclusions are:1. The experimental research on the characteristics of the typical runaway operating mode.There have induced six kinds of the typical runaway operating mode according to the actual conditions of the power system. And under the condition that assure the safety, the article made the research of the runaway operating mode' characteristics under the condition that stopping the pump after brief steady with starting with load, and got a batch of achievements:1) The transient law of the pressure and flow in the import and exit of the pump;2) The transient law of the pressure in the middle of the pipeline;3) The transient law of the pressure and flow in the import and exit of the pipeline;4) The changing law of the rotating moment of the pump.2. Discuss and analyse the basic characteristics that may appear in the runaway operating mode.1) The runaway mode will bring two consequences: the first is there have not transient phenomena or there have only weak transients , the second is there havethe strong transients.2) Under the research of the article, there may appear the strong transients in starting the pump with load, there have not transients or have only weak transients in the stopping with load. 3. Analyse the two kinds of runaway operating mode' characteristics. The two modes are the starting with load and the stopping with load. The characteristics are:1) The characteristics of time. Including:The time without pressure and flow output in the exit of the pump; The time with negative pressure and flow backwards in the middle and exit of the pipeline; The time of pressure' vibration in the import and exit of the pump , the middle and exit of the pipeline ;The time of the flow' vibration in the exit of the pump and the pipeline.2) The frequency and extent characteristics of the transient pressure and flow.The frequency and extent of the pressure in the import and exit of the pump, the middle of the pipeline and the exit of the system; the frequency and extent of the flow in the exit of the pump andthe pipeline.3) The changing characteristics of the pump' rotating moment.4. Put forward the new conception of HL.1) Define the ratio between the depth in the upper reaches (or pressure) and the length of the whole pipeline as HL;2) Count and analyse the relation between the HL and the transient parameters under the mode of starting with load;3) Give out the range of the HL that can distinguish the strong transients from the weak transients.5. Put forward the methods and way that can control the runaway operating mode' characteristics.1) The transient intensity of the runaway operating mode can be controlled by controlling the HL of the system;2) Under the research of the article , there will occur the strong transients when the HL ≥ 6.25 and ≤ 0.19,while there will have not transients or have the weak t...