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1、Synthetic platform detail introduction,Contents,Why to build up synthetic platform Switchgear making & breaking testing techniques Energy Sh-Lab synthetic platform structure,Why to build up synthetic platform,Process needs & limits from conventional test plant,Single phase testing accounts for 70% o
2、f the total development testing,Conventional test plant generator or network Large, cumbersome to operate Expensive Difficult to make analysis if test failed,Three phase short power needs for direct testing,Above table shows the three phase short circuit power that is required from the primary sourc
3、e (generator or public network) to perform direct tests on MV CB for the IEC rated values. The approximate cost of a 2000MVA station powered by short circuit generator is 200 million RMB.,Principle of synthetic test,Divide short-circuit breaking into 2 phases to reduce necessary power High current p
4、hase (short-circuit) High voltage phase (Transient recovery voltage) High current phase: supply the short circuit test current from a source of much lower voltage than the breaker rated voltage High voltage phase: provide voltage stress after interruption from a low power high voltage sorce Syntheti
5、c lab is thus composed of 2 banks A high current one A high voltage one with good time coordination between both,Advantage of synthetic testing,Effectiveness: Widely accepted as an equivalent method as direct testing. Efficiency: Producing large number of tests quickly. Economic: Significant cost re
6、duction on the installation compare with the cost of power source needed for direct testing. Easy to operate and maintain. Protection of prototype under test: Significantly reduction of damage to the prototype even if the test failed. Convenience for analysis Provide possibility to stop testing when
7、 time analysis of results or prototype modification is needed. Suitable environment to attempt the sophisticated measurements required to know what is happening in the interrupter, particularly during the few vital microseconds immediately before and after current zero.,Switchgear making & breaking
8、testing techniques,3 basic types of short circuit test for MV & HV CB,Short circuit current making & breaking test Load current making & breaking test Short time withstand & peak withstand current test,The most demanding test for CB is the breaking of its rated short circuit current. Most of the tes
9、t station are fed by specially designed short circuit generator, while others are connected directly to the public network. Certification tests on MV SWGR are always carried out by direct tests, i.e. the short circuit current supplied from a source with an open circuit voltage equal to the rated vol
10、tage of the CB. Certification test on HV SWGR are normally carried out by synthetic tests due to the capacity limits of the source.,IEC short circuit test requirements,Test duty 1,2,3&4 involve breaks with symmetrical currents Test duty 5 is known as “break with asymmetrical currents” and the severi
11、ty of the test strongly depends on the instant of contact separation. The standard requires that timing is adjusted so that the FPTC separates its contacts in a major loop of current.,Remark (*): The % of DC component is referred to the a.c. component for a time constant of 45ms (X/R=14),Load curren
12、t making & breaking tests,Load currents making & breaking tests do not normally impose a demanding duty on the switchgear as fault currents do. However, switch failure like reignitions or current chopping can cause severe over-voltage and damage the load insulation. Testing is required in particular
13、 for the disconnection to capacitive loads (like power factor correction capacitor & unloaded cables) & inductive loads (like induction motors & unloaded transformers) for two main reason: To satisfy customer, who is mainly concerned with maximum overvoltage likely to be generated by the SWGR in ser
14、vice and its relation to the insulation level of the network where it is going to be installed. To allow designer to find a compromise between the divergent duties imposed on the switching devices. No standard test has been agreed yet for inductive load current as the chopping level and over-voltage
15、 are strongly dependent on the interaction between the CB and local stray capacitance and inductance in the circuit These type of tests are normally carried out as direct tests as the power required from the source is very small compare to the short circuit tests.,Short time & peak withstand current
16、 test,This test is intended to verify the ability of the SWGR main contact system and mechanical structure to withstand the thermal & electrodynamic stress imposed by the rated short circuit current passing through the device in closed position for several seconds (1/3/4s).The absence of the arc impedance allows the possibility to supply the short circuit current from a low voltage source (100V or less). This results in a low power high current source which can be easily fed from the public network without causing disturbances to other users.,
