A converter arrangement comprising: a power converter ; circuit breakers configured to be connected to an AC mains ; converter terminals for connecting the power converter to the AC mains via the circuit breakers ; and an auxiliary power supply arrangement comprising: switches arranged to connect the power supply arrangement to the converter terminals ; an auxiliary power supply and charging breakers , wherein the auxiliary power supply is connected via the charging breakers to the converter terminals between the power converter and the circuit breakers , wherein the auxiliary power supply is configured for charging gate units of cell switches (S) of at least one converter cell of the power converter during start-up of the power converter; a transformer for increasing the voltage from the auxiliary power supply to the power converter , wherein the transformer is connected between the charging breakers and the switches of the auxiliary power supply arrangement ; and a capacitor arrangement comprising at least one capacitor, connected between the charging breakers and the converter terminals on the low-voltage side of the transformer and/or on the high-voltage side of the transformer ; wherein the capacitor arrangement is configured to protect semiconductors of the cell switches (S) from voltage surges (dv/dt) during the start-up of the power converter . a power converter ; circuit breakers configured to be connected to an AC mains ; converter terminals for connecting the power converter to the AC mains via the circuit breakers ; and an auxiliary power supply arrangement comprising: switches arranged to connect the power supply arrangement to the converter terminals ; an auxiliary power supply and charging breakers , wherein the auxiliary power supply is connected via the charging breakers to the converter terminals between the power converter and the circuit breakers , wherein the auxiliary power supply is configured for charging gate units of cell switches (S) of at least one converter cell of the power converter during start-up of the power converter; a transformer for increasing the voltage from the auxiliary power supply to the power converter , wherein the transformer is connected between the charging breakers and the switches of the auxiliary power supply arrangement ; and a capacitor arrangement comprising at least one capacitor, connected between the charging breakers and the converter terminals on the low-voltage side of the transformer and/or on the high-voltage side of the transformer ; wherein the capacitor arrangement is configured to protect semiconductors of the cell switches (S) from voltage surges (dv/dt) during the start-up of the power converter . switches arranged to connect the power supply arrangement to the converter terminals ; an auxiliary power supply and charging breakers , wherein the auxiliary power supply is connected via the charging breakers to the converter terminals between the power converter and the circuit breakers , wherein the auxiliary power supply is configured for charging gate units of cell switches (S) of at least one converter cell of the power converter during start-up of the power converter; a transformer for increasing the voltage from the auxiliary power supply to the power converter , wherein the transformer is connected between the charging breakers and the switches of the auxiliary power supply arrangement ; and a capacitor arrangement comprising at least one capacitor, connected between the charging breakers and the converter terminals on the low-voltage side of the transformer and/or on the high-voltage side of the transformer ; wherein the capacitor arrangement is configured to protect semiconductors of the cell switches (S) from voltage surges (dv/dt) during the start-up of the power converter . <EOS>