The invention relates to an arrangement for measuring salinity in water, which arrangement is part of an impressed current cathodic protection system having an electrical circuit comprising a source of electrical power (310); at least one first electrode (315) connected to a positive pole of the power source (310); at least one second electrode (317) connected to a negative pole of the power source (310); a voltage sensor (341); a current sensor (342); and a control unit (313). The control unit is arranged to initiate a measurement sequence at predetermined intervals, wherein the control unit is arranged to connect at least one first electrode (315) to the negative pole of the power source (310) to act as a cathode; connect at least one passive electrode (326) to the positive pole of the power source (310) to act as an active anode; register the output voltage; register the current; determine the circuit resistance using the output voltage and the current; and calculate the resistivity of the electrolyte based on the determined circuit resistance and at least one stored electrode property value, which resistivity is inversely proportional to the salinity. The invention further relates to a vessel provided with such a measuring arrangement and a method for its operation.

The invention relates to an arrangement for measuring salinity in water, which arrangement is part of an impressed current cathodic protection system having an electrical circuit comprising a source of electrical power (310); at least one first electrode (315) connected to a positive pole of the power source (310); at least one second electrode (317) connected to a negative pole of the power source (310); a voltage sensor (341); a current sensor (342); and a control unit (313). The control unit is arranged to initiate a measurement sequence at predetermined intervals, wherein the control unit is arranged to connect at least one first electrode (315) to the negative pole of the power source (310) to act as a cathode; connect at least one passive electrode (326) to the positive pole of the power source (310) to act as an active anode; register the output voltage; register the current; determine the circuit resistance using the output voltage and the current; and calculate the resistivity of the electrolyte based on the determined circuit resistance and at least one stored electrode property value, which resistivity is inversely proportional to the salinity. The invention further relates to a vessel provided with such a measuring arrangement and a method for its operation.

A method for changing an activation state of an interruption module for selectively interrupting at least one passive cathodic protection unit from a metallic structure. The method includes enabling a global positioning system (GPS) receiver in data communication with a controller of the interruption module, receiving GPS time via the GPS receiver from at least one global positioning system satellite in data communication therewith, synchronizing a real-time clock time of a real-time clock in data communication with the controller to GPS time, disabling the GPS receiver and changing the activation state of the interruption module if a predetermined activation state change time of the interruption module is between the local real-time clock time and the GPS time.

A method for changing an activation state of an interruption module for selectively interrupting at least one passive cathodic protection unit from a metallic structure. The method includes enabling a global positioning system (GPS) receiver in data communication with a controller of the interruption module, receiving GPS time via the GPS receiver from at least one global positioning system satellite in data communication therewith, synchronizing a real-time clock time of a real-time clock in data communication with the controller to GPS time, disabling the GPS receiver and changing the activation state of the interruption module if a predetermined activation state change time of the interruption module is between the local real-time clock time and the GPS time.

An intelligent system is provided for monitoring a subsea structure and delivering appropriate cathodic protection to desired areas of the subsea structure. According to an embodiment, the technique involves monitoring a cathodic protection potential level at an important location or locations of the subsea structure. Based on the data acquired via monitoring, a controller is able to apply voltage levels to the subsea structure so as to attain and modulate a desired cathodic protection level, e.g. a cathodic protection level within a range of about −800 mV to −950 mV (SCE). Consequently, undesirable overprotection and under protection are avoided and the subsea structure is adequately protected from corrosion while reducing undesirable production of hydrogen.

An intelligent system is provided for monitoring a subsea structure and delivering appropriate cathodic protection to desired areas of the subsea structure. According to an embodiment, the technique involves monitoring a cathodic protection potential level at an important location or locations of the subsea structure. Based on the data acquired via monitoring, a controller is able to apply voltage levels to the subsea structure so as to attain and modulate a desired cathodic protection level, e.g. a cathodic protection level within a range of about −800 mV to −950 mV (SCE). Consequently, undesirable overprotection and under protection are avoided and the subsea structure is adequately protected from corrosion while reducing undesirable production of hydrogen.

Assemblies and methods for monitoring the cathodic protection of underground or submerged structures may include a coupon assembly including a conductive test coupon and a reference electrode for determining the voltage potential difference of the protected structure without substantially interrupting surrounding current sources. The reference electrode may be at least partially covered with an electrolytic material in electrical contact with the surrounding environment via a plug including a porous material. A method of installation of the assembly may allow a single technician to install the coupon assembly using a probe rod without extensive on-site excavation. The coupon assembly may be configured to seat securely with the probe rod for stability during installation, and release from the probe rob when the probe rod is separated from the coupon assembly and withdrawn from the ground, leaving the coupon assembly at a preselected depth or preselected distance from the protected structure.

A system is disclosed for controlling an electrochemical process. The system has a power source that is coupled to a power amplifier. The power amplifier is configured to provide an electromotive force (emf) signal, and a plurality of electrodes apply the emf signal to an electrochemical solution. A control element is configured to control the power amplifier such that the emf signal exhibits a predetermined frequency, amplitude, and duty cycle for reducing a thickness of the Nernst diffusion layer such that an operational parameter is set to a predetermined value.

A system is disclosed for controlling an electrochemical process. The system has a power source that is coupled to a power amplifier. The power amplifier is configured to provide an electromotive force (emf) signal, and a plurality of electrodes apply the emf signal to an electrochemical solution. A control element is configured to control the power amplifier such that the emf signal exhibits a predetermined frequency, amplitude, and duty cycle for reducing a thickness of the Nernst diffusion layer such that an operational parameter is set to a predetermined value.

A system, apparatus, and method for analyzing cathodic protection (CP) current shielding of a coating are provided. The system includes: a test cell configured to have a coating film disposed therein and to be filled with electrically conductive solution surrounding the coating film; an electrical resistance (ER) probe mounted through a port of the test cell; and a potentiostat configured to: apply potential to the test cell to thereby polarize a sensing element of the ER probe such that the ER probe is configured to measure data indicative of a corrosion rate of the sensing element when the coating film is disposed within the test cell and while a CP current flows through the sensing element; and measure a current density through the sensing element in order to indicate an extent of CP current shielding of the coating film.