Construction of substation 220 kV Lafarge. Volume 2. Relay protection and automation, страница 4

Nominal line voltage                                                          U_nom = 100 V

Nominal 3U₀  voltage                                                         U_nom = 100 V

Rated thermal voltage                                                        1,5×U_nom (long)

One second resistance voltage                                           2,5×U_nom

Rated 3U₀ thermal voltage                                                 1,5×U_nom

One second 3U₀ resistance voltage                                    2,5×U_nom

Operating voltage range                                                                                                  (0,005I1,5)×U_nom

Consumption per phase at U_nom                                          < 0,5 V∙А

Consumption by 3U₀ at U_nom                                              < 1,0 V∙А

3.3. Operating frequency of the terminals

Nominal frequency                                                             f_nom = 50 Hz

Operating frequency range                                                                                                   (0,95I1,05)×f_nom

3.4. Direct voltage circuits of the terminals

Nominal voltage                                                                 U_nom = 110 V

Operating voltage range                                                     (0,8I1,1) ×U_nom

Consumption at normal operating condition

at U_nom (with no short-circuit)                                            P_nom < 50 Wt

Consumption at short-circuit                                              < 2×Р_nom

Direct voltage ripple is not more than 6 % of average level.

Voltage disappearance or reduction below the limit for up to 0.05 seconds shall not violate the normal functioning of the terminals.

Connecting the terminals to the voltage of reverse polarity must not cause damage to them.

3.5. Binary inputs of the terminals

Nominal direct voltage of each input                                 U_nom.input = 110 В

Current of each input should provide the breakdown of the control contacts oxide film, so the initial current pulse should be I_BI.pulse ≥ 50 mA, and then may be reduced.

Inputs should have no galvanic coupling with the internal working circuits of the terminal.

Binary inputs of the terminals, which receive the signals from the protections or devices located at the open high-voltage switchgear (namely, gas protection of the transformer), and their circuits should have resistance that ensures operation of the insulation control device (for earth faults in DC circuits), which has the threshold of 20 ohms.

3.6. Outputs of the terminals

Outputs should be contact type and have no galvanic coupling with the internal working circuits of the terminal.

Outputs must have both normally closed and open contacts.

Each contact must provide opening with next values of current: 1/0,4/0,2/0,15 A at the voltages of 48/110/220/250 V and time constant of the L/R circuit ≤ 50 ms.

Contacts, which commute circuit breaker trip circuits, must also ensure:

- closing up to 10 А (t =1,0 sec);

- closing up to 30 А (t=0,2 sec);

- prolonged current flow of 5 А.

Switching capacity of relay contacts, operating in the external alarm circuit, shall be not less than 30 watts in operating direct circuits with active-inductive load, time constant less than 0,02 sec, voltage up to 250 V and current up to 2 A.

3.7. The Terminals should have programmable logic between different protection, management and control functions presented in MP relays, and also between this functions and external protection, management and control devices.

In addition, there should be free logic elements, allowing adapting the terminals to the peculiarities of the substation.

3.8. The terminals should meet the following regulations:

- insulation level – GOST R 50514-93 (IEC 255-5-77);

- interference immunity – GOST 51317.6.5-2006 (IEC 61000-6-5:2001), «Guidelines for electromagnetic compatibility of secondary equipment and communication systems of the power grid» (SТО 56947007-29.240.043-2010), « Guidelines for the provision of electromagnetic compatibility of the power grid» (SТО 56947007-29.240.044-2010);