JB/T 10303-2020Power frequency diesel generating sets - Technical requirements (English PDF)

4 Technical requirements

Table 3 gives, for each of the performance classes G1, G2 and G3, the limits of the parameters of the set. For class G4 the values are those laid down in the agreement between the manufacturer and the user.

Item 1, frequency droop, in per cent: not more than 8 for class G1, not more than 5 for G2 and not more than 3 for G3.

Item 2, steady-state frequency band, in per cent: not more than 2,5 for G1, not more than 1,5 for G2 and not more than 0,5 for G3. For a set with a single cylinder or a two cylinder engine the value for G2 may reach 2,5.

Item 3, relative downward frequency setting range, in per cent: greater than 2,5 plus the frequency droop, for all three classes.

Item 4, relative upward frequency setting range, in per cent: greater than plus 2,5. Where parallel running is not required, a fixed setting of speed and voltage is allowed.

Item 5, transient frequency deviation referred to the initial frequency, in per cent: on a sudden reduction of 100 per cent of the load, not more than plus 18 for G1, plus 12 for G2 and plus 10 for G3; on a sudden increase of load, not less than minus 15 plus the droop for G1, minus 10 plus the droop for G2 and minus 7 plus the droop for G3.

Item 6, transient frequency deviation referred to the rated frequency, in per cent: on a sudden reduction of 100 per cent of the load, not more than plus 18, plus 12 and plus 10; on a sudden increase of load, not less than minus 15, minus 10 and minus 7.

Item 7, frequency recovery time, in seconds: on a sudden reduction of load not more than 10, 5 and 3; on a sudden increase of load not more than 10, 5 and 3.

Item 8, relative frequency tolerance band, in per cent: 3,5 for G1 and 2 for G2 and G3.

Item 9, steady-state voltage deviation, in per cent: from minus 5 to plus 5 for G1, from minus 2,5 to plus 2,5 for G2 and from minus 1 to plus 1 for G3. For small sets not exceeding 10 kVA the range for G1 is from minus 10 to plus 10, and where the reactive current characteristic is taken into account the range for G2 is from minus 5 to plus 5.

Item 10, voltage modulation, in per cent: by agreement for G1, 0,3 for G2 and 0,3 for G3.

Item 11, transient voltage deviation, in per cent: on a sudden reduction of 100 per cent of the load, not more than plus 35, plus 25 and plus 20; on a sudden increase of load, not less than minus 25, minus 20 and minus 15.

Item 12, voltage recovery time, in seconds: on a sudden reduction of load not more than 10, 6 and 4; on a sudden increase of load not more than 10, 6 and 4.

Item 13, relative voltage setting range, in per cent: not more than minus 5 and not less than plus 5.

Item 14, rate of change of the voltage setting: from 0,2 to 1 per cent per second.

Item 15, rate of change of the frequency setting: from 0,2 to 1 per cent per second.

Item 16, active power sharing, in per cent: between 80 and 100 per cent of the declared rating, from minus 5 to plus 5; between 20 and 80 per cent, from minus 10 to plus 10. No value is given for class G1.

Item 17, reactive power sharing, in per cent: between 20 and 100 per cent of the declared rating, from minus 10 to plus 10. No value is given for class G1.

Item 18, voltage unbalance, in per cent: 1. In parallel running this value is reduced to 0,5.

Note to items 5, 6, 7, 11 and 12: for sets with a turbocharged engine these figures apply to the maximum permissible load increase given in Figure 6 of GB/T 2820.5-2009.

Note to item 12: unless otherwise specified, the tolerance band used to calculate the voltage recovery time is equal to twice the steady-state voltage deviation multiplied by the rated voltage and divided by 100.

Note to item 16: where this tolerance band is used, the total active or reactive declared load of the sets running in parallel is reduced by the amount of the tolerance.

5 Inspection rules

6 Inspection items and methods

7 Marking, packaging, transport and storage

8 Guarantee of the manufacturer