5.3 Signal transmission characteristics
5.3.1 Power line carrier channel
5.3.1.1 Signal frequency band
    When the power line carrier communication is adopted, the frequency scope of the carrier should be 3kHz~500kHz and the dedicated frequency band for electric power departments 9kHz~95kHz specified by IEC61000-3-8 should be considered first. The frequency band used by the system should be approved by the appropriate electric power department.
5.10 Reliability requirement
    The average work time without malfunctions (MTBF) for the equipments in the system shall be no less than 7.6×10⁴h.
6.9 Safety performance tests
6.9.1 Normal test conditions（Ellipsis）
6.9.2 Insulating resistance test
    The insulating resistances between electric circuits and the ground and those between circuits and circuits are measured by the 500V meter. The insulating resistances shall not be less than 5Mohm under normal conditions and 2MΩ after the humidity and temperature test.
6.9.3 Pulse voltage test
◆ The test shall be conducted under the following conditions:
◆ pulse shape: the standard 1.2/50μs pulse;
◆ voltage ascending time: ±30%;
◆ voltage descending time: ±20%;
◆ power source resistance: 500±50Ω;
◆ power source energy: 0.5±0.05J
◆ testing voltage: 6kV;
◆ allowed error of testing voltage: +0%,-10%.
    Pulse voltage shall be put for different polarities for 10 times for each test and the minimum interval between pulses is 3s.
    a) The pulse voltage tests between circuits and circuits shall be conducted separately for every mutually isolated circuits (or circuit combinations) when the system and its composing equipments are running normally and the end of untested circuit shall be connected to the ground.
    If the several power source voltage circuits of the system and its composing equipments have a point in common, this point shall be connected to the ground and the pulse voltage shall be put between every unconnected end and the ground serially.
    b) The pulse voltage test of the circuit to the ground shall be conducted separately for the system and its composing equipments.
    All the circuit ends of the system and its composing equipments, including the auxiliary circuit ends with referred voltage larger than 40V, shall be connected mutually.
    The auxiliary circuits with referred voltage less than or equal to 40V shall be connected to the ground and the pulse voltage is added between all the circuits and the ground.
6.9.4 Alternating voltage test
    The parameters of testing voltage are:
◆ voltage shape: actual sine wave;
◆ amplitude: 2kV;
◆ frequency: 45Hz~65Hz;
◆ adding time: 1min;
◆ power source capacity: ≥500VA.
    The testing voltage is added to the circuit and the ground, that is:
    All the circuit ends of the power and others with referred voltage larger than 40V are connected together to be one end and the other end is the ground.
6.10 Electromagnetic compatibility tests
6.10.1 Normal test conditions
    In all the following tests, the system and its composing equipments are in their normal working locations and all the accessories that shall be connected to the ground are connected to the ground.
    The system and its composing equipments shall not occur damages after the tests and can work correctly and normally.
6.10.2 Electrostatic discharge immunity test
    The test shall be conducted according to IEC1000-4-2: 1995 under the following conditions:
◆ osculation discharge;
◆ asperity grade: 4;
◆ testing voltage: 8kV;
◆ on the shell and operating keys of the tested equipment that can be often touched by the working staff;
◆ discharge occurrence: 10 times, at least 1s for each interval between discharges.
    a)The system and its composing equipments are not working:
the power sources and auxiliary circuits are not electrified;
All the power sources and auxiliary circuits are connected together;
after the electrostatic discharge, the system and its composing equipments shall not occur damages or changes of information and can work and communicate normally.
    b)The system and its composing equipments are working:
referred voltages are added to the power sources and auxiliary circuits;
after the electrostatic discharge, the system and its composing equipments shall not occur damages or changes of information and can work and communicate normally.
6.10.3 Radiated, radio-frequency, electromagnetic field immunity test
    The test shall be conducted according to IEC1000-4-3: 1995 under the following conditions:
referred voltages are added to the power sources and auxiliary circuits and the equipments of the system are working normally;
◆ frequency scope: 80MHz~1000MHz;
◆ asperity grade: 3;
◆ testing field intensity: 10V/m.
    a) Wireless communication system:
    When the acquisition terminal units (or acquisition modules) are not acquiring data, the information in memory of the tested system and its composing equipments shall not change.
When the acquisition terminal units (or acquisition modules) are acquiring data, the tested system shall record normally.
    For the above two states, the system shall receive correctly in the utilized frequency band and shall work normally; for radiated immunity of other frequencies, the system shall also work and communicate normally.
    b) Wired communication system
    When the acquisition terminal units (or acquisition modules) are not acquiring data, with the radiated immunity, the information in memory of the tested system and its composing equipments shall not change and the system shall work and communication normally.
    When the acquisition terminal units (or acquisition modules) are acquiring data, with the radiated immunity, the tested system shall record normally and shall work and communicate normally.
6.10.4 Electrical fast transient/burst immunity test
    The test shall be conducted according to IEC1000-4-4: 1995 under the following conditions:
the testing voltages are added in the method of common mode between the ground and the system and between the following circuits of the equipments:
◆ power source voltage circuits;
◆ auxiliary circuits isolated with the power source voltage circuit during normal work;
◆ input/output and data communication circuits;
    a) When acquisition terminal units (or acquisition modules) are acquiring data:
◆ referred voltages are added to the power sources and auxiliary circuits;
◆ asperity grade: 3;
◆ testing voltages of the power sources and auxiliary circuits: 2kV;
◆ testing time: three times of 1s each distributed equally in 10min.
    Under the effect of burst, the system and its composing equipments shall not occur damages and shall work and count numbers normally. The veracity of electricity readings shall meet the requirements and the system shall work and communicate normally after the test.
    b) When acquisition terminal units (or acquisition modules) are not acquiring data:
◆ referred voltages are added to the power sources and auxiliary circuits;
◆ asperity grade: 4;
◆ testing voltages of the power sources and auxiliary circuits: 4kV;
◆ testing time: 60s.
    Under the effect of burst, the system and its composing equipments shall not occur damages or changes of information and shall work normally. The system shall work and communicate normally after the test.
    c) When acquisition terminal units (or acquisition modules) are not acquiring data (the testing voltage is coupled to the circuit with the capacitance coupling clincher):
◆ referred voltages are added to the power sources and auxiliary circuits;
◆ asperity grade: 3;
◆ testing voltages coupled to the input/output signal, data, control and communication circuits: 1kV;
◆ testing time: 60s.
    Under the effect of burst, the system and its composing equipments shall not occur damages or changes of information and shall work normally. The system shall work and communicate normally after the test.
    d) When acquisition terminal units (or acquisition modules) are acquiring data, the testing voltage is coupled to the pulse transmission circuit with the capacitance coupling clincher (this test is only for the system that need to connect the acquisition terminal unit and pulse electricity meter with a pulse transmission line longer than 1m):
◆ referred voltages are added to the power sources and auxiliary circuits;
◆ asperity grade: 3;
◆ testing voltages coupled to the pulse transmission line: 1kV;
◆testing time: 60s.
    Under the effect of burst, the system and its composing equipments shall not occur damages and shall work and count numbers normally. The system shall work and communicate normally after the test.
6.10.5 Surge immunity test
    The test shall be conducted according to IEC1000-4-4: 1995 under the following conditions:
the testing voltage shall be added between the following circuits (ends):
◆ power source voltage circuit ends;
◆ auxiliary circuit ends isolated with the power source voltage circuits during normal working;
power source voltage circuit ends and the ground;
◆ auxiliary circuit ends isolated with the power source voltage circuits during normal working and the ground.
    When the acquisition terminal units (or acquisition modules) are not acquiring:
◆ referred voltages are added to power source circuits and auxiliary circuits;
◆ wave shape: 1.2/50μs;
◆ polarity: positive, negative;
◆ test occurrence: 5 times for positive and negative polarity each;
◆ repetition: 1/min.
    a) between the circuit ends:
◆ asperity grade: 3;
◆ testing voltage: 2kV.
    b) between the circuit ends and the ground:
◆asperity grade: 4;
◆ testing voltage: 4kV.
    The equipments shall not be damaged during the test. After the test, the data saved in the system shall not change and the system can work and communication normally.
6.10.6 Impact test of working frequency electromagnetic field
    Under the normal working state, the equipments are put in the center of the winding that generates an even distributed electromagnetic field with the same frequency as the power source voltage of the system, shape of sine wave, and intensity of 0.5mT (400A/m). The direction of the electromagnetic field winding and the phase of current in the winding shall be adjusted such that the most disadvantageous direction and phase are obtained. The system performance shall meet the requirements in 5.9 during the test.
6.11 Reliability validation test
   The reliability validation test shall be conducted in the site acceptance test. Appendix B.2.7 shall be referred.